In a particular crash test, an automobile of mass 1577 kg collides with a wall and bounces back off the wall. The x components of the initial and final speeds of the automobile are 17 m/s and 1.5 m/s, respectively. If the collision lasts for 0.18 s, find the magnitude of the impulse due to the collision. Answer in units of kg · m/s.

Answers

Answer 1

Answer:

Ft=24,443.5 kgm/s

Explanation:

Step one

Given data

Mass of automobile m=1577kg

Initial Velocity u=17m/s

Final Velocity v=1.5m/s

Time t=0.18s

Step two

From the impulse and momentum equation

Ft=mΔv

Substitute

Ft=1577*(17-1.5)

Ft=1577*15.5

Ft=24,443.5 kgm/s


Related Questions

Allen and Jason are chucking a speaker around. On one particular throw, Allen throws the speaker, which is playing a pure tone of frequency f, at a speed of 10 m/s directly towards Jason, but his aim is a bit off. As a result, Jason runs forward towards the speaker at a speed of 6 m/s before catching it. Then, the frequency that Jason hears while running can be written as (m/n)f Hz, where m and n are relatively prime positive integers. Compute m n.

Answers

Answer:

Explanation:

We shall apply Doppler's effect of sound .

speaker is the source , Jason is the observer . Source is moving at 10 m /s , observer is moving at  6 m/s .

apparent frequency = [tex]f_o\times\frac{V+v_o}{ V-v_s}[/tex]

V is velocity of sound , v₀ is velocity of observer and v_s is velocity of source and f_o is real frequency of source .

Here V = 340 m/s , v₀ is 6 m/s , v_s is 10 m/s . f_o = f

apparent frequency =  [tex]f\times \frac{340+6}{340-10}[/tex]

= [tex]f\times \frac{346}{330}[/tex]

So m = 346 , n = 330 .

A block weighing 9.3 N requires a force of 3.7 N to push it along at constant velocity. What is the coefficient of friction for the surface

Answers

Answer:

0.398

Explanation:

According to friction, the frictional force is directly proportional to the normal reaction

Ff = nR

Ff is the frictional force

n is the coefficient of friction

R is the reaction

Reaction is equal to the weight

R= W = 9.3N

Fm = Ff = 3.7N

Fm is the moving force

Get the coefficient of friction

n = Ff/R

n = 3.7/9.3

n = 0.398

Hence the coefficient of friction for the surface is 0.398

The resistance of a wire depends on its length i and on its cross sectional area A the resistance is

Answers

Answer:

The resistance of a wire is directly proportional to its length and inversely proportional to its cross-sectional area

Explanation:

Suppose the maximum safe intensity of microwaves for human exposure is taken to be 1.00 W/m2 . (a) If a radar unit leaks 10.0 W of microwaves (other than those sent by its antenna) uniformly in all directions, how far away must you be to be exposed to an intensity considered to be safe

Answers

Answer:

We must be approximately at least 1.337 meters away to be exposed to an intensity considered to be safe.

Explanation:

Let suppose that intensity is distributed uniformly in a spherical configuration. By dimensional analysis, we get that intensity is defined by:

[tex]I = \frac{\dot W}{\frac{4\pi}{3}\cdot r^{3}}[/tex] (1)

Where:

[tex]I[/tex] - Intensity, measured in watts per square meter.

[tex]r[/tex] - Radius, measured in meters.

If we know that [tex]\dot W = 10\,W[/tex] and [tex]I = 1\,\frac{W}{m^{2}}[/tex], then the radius is:

[tex]r^{3} = \frac{\dot W}{\frac{4\pi}{3}\cdot I }[/tex]

[tex]r = \sqrt[3]{\frac{3\cdot \dot W}{4\pi\cdot I} }[/tex]

[tex]r = \sqrt[3]{\frac{3\cdot (10\,W)}{4\pi\cdot \left(1\,\frac{W}{m^{2}} \right)} }[/tex]

[tex]r \approx 1.337\,m[/tex]

We must be approximately at least 1.337 meters away to be exposed to an intensity considered to be safe.

A small lead ball, attached to a 1.10-m rope, is being whirled in a circle that lies in the vertical plane. The ball is whirled at a constant rate of three revolutions per second and is released on the upward part of the circular motion when it is 1.3 m above the ground. The ball travels straight upward. In the absence of air resistance, to what maximum height above the ground does the ball rise

Answers

Answer:

1.84 m

Explanation:

For the small lead ball to be balanced at the tip of the vertical circle just before it is released, the reaction force , N equal the weight of the lead ball W + the centripetal force, F. This normal reaction ,N also equals the tension T in the string.

So, T = mg + mrω² = ma where m = mass of small lead ball, g = acceleration due to gravity = 9.8 m/s², r = length of rope = 1.10 m and ω = angular speed of lead ball = 3 rev/s = 3 × 2π rad/s = 6π rad/s = 18.85 rad/s and a = acceleration of normal force. So,

a = g + rω²

= 9.8 m/s² + 1.10 m × (18.85 rad/s)²

= 9.8 m/s² + 390.85 m/s²

= 400.65 m/s²

Now, using v² = u² + 2a(h₂ - h₁)  where u = initial velocity of ball = rω = 1.10 m × 18.85 rad/s = 20.74 m/s, v = final velocity of ball at maximum height = 0 m/s (since the ball is stationary at maximum height), a = acceleration of small lead ball = -400.65 m/s² (negative since it is in the downward direction of the tension), h₁ = initial position of lead ball above the ground = 1.3 m and h₂ = final position of lead ball above the ground = unknown.

v² = u² + 2a(h₂ - h₁)

So, v² - u² = 2a(h₂ - h₁)

h₂ - h₁ =  (v² - u²)/2a

h₂ =  h₁ + (v² - u²)/2a

substituting the values of the variables into the equation, we have

h₂ =  1.3 m + ((0 m/s)² - (20.74 m/s)²)/2(-400.65 m/s²)

h₂ =  1.3 m + [-430.15 (m/s)²]/-801.3 m/s²

h₂ =  1.3 m + 0.54 m

h₂ =  1.84 m

A cart's initial velocity is +3.0 meters per second. What is its final velocity after accelerating at a rate of 1.5 m/s2 for 8.0 seconds?
A. 36 m/s
B. 9 m/s
C. 72 m/s
D. 15 m/s​

Answers

Answer:

V = 15m/s

Explanation:

Given the following data;

Initial velocity = 3m/s

Time = 8secs

Acceleration = 1.5m/s²

To find the final velocity, we would use the first equation of motion;

V = U + at

Substituting into the equation, we have

V = 3 + 1.5*8

V = 3 + 12

V = 15m/s

An inductor is connected to a 120-V, 60-Hz supply. The current in the circuit is 2.4 A. What is the inductive reactance

Answers

Answer:

Inductive reactance is 50.00 ohms

Explanation:

Given the following data;

Voltage = 120v

Frequency = 60Hz

Current = 2.4 A

To find the inductive reactance;

Inductive reactance, XL = V/I

Where;

XL represents the inductive reactance. V represents the voltage. I represents the current.

Substituting into the equation, we have;

XL = 120/2.4

XL = 50.00 ohms

Water runs out of a horizontal drainpipe at the rate of 135 kg/min. It falls 3.1 m to the ground. Assuming the water doesn't splash up, what average force does the water exert on the ground

Answers

Answer:

The average force exerted by the water on the ground is 17.53 N.

Explanation:

Given;

mass flow rate of the water, m' = 135 kg/min

height of fall of the water, h = 3.1 m

the time taken for the water to fall to the ground;

[tex]h = ut + \frac{1}{2}gt^2\\\\h = 0 + \frac{1}{2}gt^2\\\\t = \sqrt{\frac{2\times 3.1}{9.8} } \\\\t = 0.795 \ s[/tex]

mass of the water;

[tex]m = m't\\\\m = 135 \ \frac{kg}{min} \ \times \ 0.795 \ s \ \times \ \frac{1 \ \min}{60 \ s} \ = 1.789 \ kg[/tex]

the average force exerted by the water on the ground;

F = mg

F = 1.789 x 9.8

F = 17.53 N

Therefore, the average force exerted by the water on the ground is 17.53 N.

A motorcycle moving 18.8 m/s has
57800 J of KE. What is its mass?

Answers

Answer:

m = 327.07 kg

Explanation:

Given that,

Kinetic energy of a motorcycle, E = 57800 J

Velocity of the motorcycle, v = 18.8 m/s

We need to find the mass of the motorcycle. The kinetic energy of an object is given by :

[tex]E=\dfrac{1}{2}mv^2[/tex]

m is mass

[tex]m=\dfrac{2E}{v^2}\\\\m=\dfrac{2\times 57800 }{(18.8)^2}\\\\m=327.07\ kg[/tex]

So, the mass of the motorcycle is 327.07 kg.

2. A 2500 kg car is slowed down uniformly from an initial velocity of 20.0 m/s to
the north by a 6250 N braking force acting opposite the car's motion. Use the
impulse-momentum theorem to answer the following questions:
a. What is the car's velocity after 2.50 s?
b. How far does the car move during 2.50 s?
c. How long does it take the car to come to a complete stop?

Answers

Answer:

13.75m/s; 42.2m; 8s

Explanation:

(a) the car's velocity after 2.50 s is 13.75 m/s

(b) The distance traveled by the car is 42.18 m

(c)  the time taken for the car to come to complete stop is 8 s.

The given parameters;

mass of the car, m = 2500 kg

initial velocity of the car, u = 20 m/s

breaking applied on the car, f = 6250 N

The acceleration of the car is calculated as follows;

[tex]F = ma \\\\a = \frac{F}{m} = \frac{6250}{2500} = 2.5 \ m/s^2[/tex]

(a) Using impulse-momentum theorem, the car's velocity after 2.5 s is calculated as follows;

[tex]F = \frac{m(u-v)}{t} \\\\m(u-v) = Ft\\\\u-v = \frac{Ft}{m} \\\\v = u - \frac{Ft}{m} \\\\v = 20 - \frac{6250 \times 2.5}{2500} \\\\v = 13.75 \ m/s[/tex]

(b) The distance traveled by the car during the 2.5 s;

[tex]v^2 = u^2 - 2as\\\\2as = u^2 - v^2\\\\s = \frac{u^2 - v^2}{2a} \\\\s = \frac{20^2 - 13.75^2}{2\times 2.5} \\\\s = 42.18 \ m[/tex]

(c) The time taken for the car to come to a complete stop;

when the car stop's the final velocity, v = 0

v = u - at

0 = 20 - 2.5t

2.5t = 20

[tex]t = \frac{20}{2.5} \\\\t = 8 \ s[/tex]

Thus, the time taken for the car to come to complete stop is 8 s.

Learn more here: https://brainly.com/question/14559060

An electron traverses a vacuum tube with a length of 2 m in 2 X 10- 4
sec. What is the average speed of the
electron during this time?

Answers

Answer:

Average speed = 10,000 m/s

Explanation:

Given the following data;

Distance = 2m

Time = 0.0002secs

To find the average speed;

Average speed = distance/time

Average speed = 2/0.0002

Average speed = 10,000 m/s

Therefore, the average speed of the

electron is 10,000 meters per seconds.

A 22.0 kg child is riding a playground merry-go- round that is rotating at 40.0 rev/min. What centripetal force must

Answers

Answer:

F = 482.51 N

Explanation:

Given that,

Mass of a child, m = 22 kg

Angular velocity of the merry-go-round, [tex]\omega=40\ rev/min[/tex]

Let the radius of the path, r = 1.25 m

We need to find the centripetal force acting on the child. The formula for the centripetal force is given by :

[tex]F=m\omega^2r\\\\=22\times (4.18879)^2\times 1.25\\\\=482.51\ N[/tex]

So, the required centripetal force is 482.51 N.

An energy source forces a constant current of 2A to flow through a light bulbfilament for twenty seconds. If 4.6 kJ is given off in the form of light and heatenergy, calculate the voltage drop across the bulb.

Answers

Answer:

The voltage drop across the bulb is 115 V

Explanation:

The voltage drop equation is given by:

[tex]V=\frac{\Delta W}{\Delta q}[/tex]

Where:

ΔW is the total work done (4.6kJ)

Δq is the total charge

We need to use the definition of electric current to find Δq

[tex]I=\frac{\Delta q}{\Delta t}[/tex]

Where:

I is the current (2 A)

Δt is the time (20 s)

[tex]2=\frac{\Delta q}{20}[/tex]

[tex]q=40 C[/tex]

Then, we can put this value of charge in the voltage equation.

[tex]V=\frac{4600}{40}=115 V[/tex]

Therefore, the voltage drop across the bulb is 115 V.

I hope it helps you!

All of the following are ways in which sports psychologists help athletes except __________.
A.
staying motivated
B.
managing fear of failure
C.
improving performance
D.
enhancing memory


Please select the best answer from the choices provided

A
B
C
D

Answers

Answer:

D-Enhancing memory

Explanation:

PLEASE PLEASE HELP!!!!

Answers

Which ones do you need help with?

A finch rides on the back of a Galapagos tortoise, which walks at the stately pace of 0.060 m>s. After 1.5 minutes the finch tires of

Answers

Complete Question:

A finch rides on the back of a Galapagos tortoise, which walks

at the stately pace of 0.060 m/s. After 1.5 minutes the finch tires of

the tortoise’s slow pace, and takes flight in the same direction for

another 1.5 minutes at 11 m/s.

What was the average speed of the  finch for this 3.0-minute interval?

Answer:

[tex]Speed = 5.53 m/s[/tex]

Explanation:

Distance is calculated as:

[tex]Distance = Speed * Time[/tex]

First, we calculate the distance for the first 1.5 minutes

For the first 1.5 minutes, we have:

[tex]Speed = 0.060m/s[/tex]

[tex]Time = 1.5\ mins[/tex]

[tex]D_2= 0.060m/s * 1.5\ mins[/tex]

Convert 1.5 mins to seconds

[tex]D_2= 0.060m/s * 1.5 * 60s[/tex]

[tex]D_2= 5.4m[/tex]

Next, we calculate the distance for the next 1.5 minutes

[tex]Speed = 11m/s[/tex]

[tex]Time = 1.5\ mins[/tex]

[tex]D_2= 11m/s * 1.5\ mins[/tex]

Convert 1.5 mins to seconds

[tex]D_2 = 11m/s * 1.5 * 60s[/tex]

[tex]D_2= 990m[/tex]

Total distance is:

[tex]Distance = 990m + 5.4m[/tex]

[tex]Distance = 995.4m[/tex]

The average speed for the 3.0 minute interval is:

[tex]Speed = \frac{Distance}{Time}[/tex]

[tex]Speed = \frac{995.4\ m}{3.0\ mins}[/tex]

Convert 3.0 minutes to seconds

[tex]Speed = \frac{995.4\ m}{3.0 * 60 secs}[/tex]

[tex]Speed = \frac{995.4\ m}{180 secs}[/tex]

[tex]Speed = 5.53 m/s[/tex]

A hammer strikes a nail with a 10 N force for 0.01 seconds. Calculate the impulse of the hammer.

Answers

Answer:

0.1Ns

Explanation:

Impulse is the product of Force and time

Impulse = Force * Time

Given

Force = 10N

Time = 0.01s

Substitute into the formula

Impulse = 10 * 0.01

Impulse = 10 * 1/100

Impulse = 10/100

Impulse = 0.1Ns

hence the impulse of the hammer is 0.1Ns

If you travel from Tucson to Argentina, you will see some different constellations in the night sky. true or false

Answers

Answer:

its true!!

Explanation: have a nice day !!

Which is greater, the energy of one photon of orange light or the energy of one quantum ofradiation having a wavelength of 3.36 * 10^-9

Answers

The question is incomplete, here is the complete question:

Which is greater, the energy of one photon of orange light or the energy of one quantum of radiation having a wavelength of [tex]3.36\times 10^{-9}m[/tex]

Answer: The energy of one quantum of radiation having wavelength [tex]3.36\times 10^{-9}m[/tex] is greater than the energy of 1 photon of orange light.

Explanation:

To calculate the energy of one photon, we use the Planck's equation:

[tex]E=\frac{N_Ahc}{\lambda}[/tex]

where,

E = energy of radiation

[tex]N_A[/tex] = Avogadro's number = [tex]6.022\times 10^{23}mol^{-1}[/tex]

h = Planck's constant = [tex]6.626\times 10^{-34}Js[/tex]

c = speed of light = [tex]3\times 10^8 m/s[/tex]

[tex]\lambda}[/tex] = wavelength of radiation

For orange light:

For 1 photon, the term [tex]N_A[/tex] does not appear

[tex]\lambda}[/tex] = 620 nm = [tex]620\times 10^{-9}m[/tex]             (Conversion factor: [tex]1nm=10^{-9}m[/tex] )

Putting values in above equation, we get:

[tex]E=\frac{6.626\times 10^{-34}Js\times 3\times 10^8m/s}{620\times 10^{-9}m}\\\\E=3.206\times 10^{-19}J[/tex]

For one quantum of radiation:

[tex]\lambda}[/tex] = [tex]3.36\times 10^{-9}m[/tex]

Putting values in above equation, we get:

[tex]E=\frac{6.022\times 10^{23}mol^{-1}\times 6.626\times 10^{-34}Js\times 3\times 10^8m/s}{3.36\times 10^{-9}m}\\\\E=3.56\times 10^{7}J/mol[/tex]

Hence, the energy of one quantum of radiation having wavelength [tex]3.36\times 10^{-9}m[/tex] is greater than the energy of 1 photon of orange light.

Brainliest brainliest help help help mememememememme

Answers

Answer:

????????????????????,

Explanation:

I need points sorry

Answer:

honestly this was so long ago can i get brainliest i need 2 more until i am at expert level

Explanation:

Which example best matches the term refraction? (17 Points)
O A. Light spreads out after it travels through a keyhole

O B. A straw in a glass of water looks bent

O C. Seeing your image in a lake

O D. An orchestra of different sounds coming together to make a larger sound​

Answers

Answer:

B

Explanation:

Just answerd that question!!!

Hope it helped!!!

.

Why could it be argued that the respiratory system is most critical to sustaining life?

Answers

Explanation:

Energy is the most important ingredient for life. Organisms use energy in diverse ways. Scientifically, energy is defined as the ability to do work. Without this ability, organisms would not exist.

So, the most important process is one that can furnish the body with energy.

The respiratory system happens to be the one that furnishes the body with energy. During respiration, the energy needs of the body is met by series of processes. Oxygen is taken in and use to liberate calories from chemical substances packed with energy. So, without respiration, the bodily energy demands will not be met.

A light ray in glass (n=1.5) hits the air-glass interface at an angle of 10 degrees from the normal. What angle from the normal is the light ray in the air (n=1.0)? (You can use the small angle approximation.)

Answers

Answer:

The angle from the normal is 15.1°.

Explanation:

We can find the angle by using Snell's law:

[tex] n_{1}sin(\theta_{1}) = n_{2}sin(\theta_{2}) [/tex]

Where:

n₁: is the first medium (glass) = 1.5

n₂: is the second medium (air) = 1.0

θ₁: is the first angle (in the glass) = 10°

θ₂: is the second angle (in the air) =?

[tex] \theta_{2} = arcsin(\frac{n_{1}sin(\theta_{1})}{n_{2}}) = arcsin(\frac{1.5*sin(10)}{1.0}) = 15.1 ^{\circ} [/tex]

Therefore, the angle from the normal is 15.1°.

I hope it helps you!        

The human nervous system can propagate nerve impulses at about 102 m>s. Estimate the time it takes for a nerve impulse to travel 2 m from your toes to your brain.

Answers

Answer:

t = 0.196 s

Explanation:

The speed of a pulse is determined by the characteristics of the medium, its density and its resistance to stress, as long as these remain the speed will be constant for which we can use the kinetic expressions of the uniform movement

          v = x / t

          t = x / v

calculate

          t = 2/102

          t = 0.196 s

Scientists create models to better understand Earth. Which evidence has led scientists to conclude that there are different layers within Earth's interior?

A.analysis of seismic wave data


B.measurement of Earth's diameter


C.temperatures taken within each layer


D.rock samples taken from Earth's core

Answers

Answer:

it is A or D

Explanation:

     

Answer:

ANswer:A

Explanation:

help mmmemememeeee I'M BEING TIMED

Answers

Answer:

it's c. or A. not b.

Explanation:

.................

A small car of mass 833 kg is parked behind a small truck of mass 1767 kg on a level road. The brakes of both the car and the truck are off so that they are free to roll with negligible friction. A 41 kg woman sitting on the tailgate of the truck shoves the car away by exerting a constant force on the car with her feet. The car accelerates at 1.5 m/s 2 . What is the acceleration of the truck

Answers

Answer: the acceleration of the truck a_t is 0.6911 m/s²

Explanation:

Given the data in the question;

There is no external force on the system; net force on the system is 0

Mass of the truck with the woman M = 1767 kg + 41 kg = 1808 kg

mass of the car m = 833 kg

car acceleration a_c = 1.5 m/s²

now let a_t be the acceleration of the truck in opposite direction

Action force on the car = Reaction force on the car

ma_c = Ma_t

a_t = ma_c / M

we substitute

a_t = (833 × 1.5) / 1808

a_t = 1249.5 / 1808

a_t = 0.6911 m/s²    

Therefore, the acceleration of the truck a_t is 0.6911 m/s²

An object with velocity 141 ft/s has a kinetic energy of 1558.71 ft∙lbf, on a planet whose gravity is 31.5 ft/s2. What is its mass in pounds

Answers

Answer:

The mass of the object is 5.045 lbm.

Explanation:

Given;

kinetic energy of the object, K.E = 1558.71 ft.lbf

velocity of the object, V = 141 ft/s

The kinetic energy of the object is calculated as;

[tex]K.E = \frac{1}{2} mV^2\\\\mV^2 = 2K.E\\\\m = \frac{2K.E}{V^2} \\\\1 \ lbf = 32.174 \ lbm.ft/s^2\\\\m = \frac{2 \ \times \ 1558.71 \ ft.lbf \ \times \ 32.174 \ lbm.ft/s^2 }{(141 \ ft/s)2 \ \ \times \ \ \ \ 1 \ lbf\ }[/tex]

[tex]m = \frac{(2 \ \times \ 1558.71 \ \times \ 32.174) \ lbm.ft^2/s^2 }{(141 )^2\ ft^2/s^2 }\\\\m = \frac{(2 \ \times \ 1558.71 \ \times \ 32.174) \ lbm }{(141 )^2 }\\\\m = 5.045 \ lbm[/tex]

Therefore, the mass of the object is 5.045 lbm.

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Gavin earned $253.00 at his job when he worked for 11 hours. How much money did he earn each hour? Which of the following is not in the Ring of Fire?A.Nicaragua B.Spain C.PanamaD.Colombia imagine you're in a queue to the airport check-in desk if two-thirds of the queue is in front of you and three tenths of the queue is behind you how many people are in the queue please answer this im going to fail Rewrite the fraction as a decimal.\dfrac{13}{10}= 1013 6 USE OF ENGLISH Complete each sentence with a wordrelated to the word in brackets. You may need to add aprefix. Use a dictionary to help you if necessary.2 He stared(envy) at his friend's new bike.3 Her neighbour is always very bad-tempered, so she foundhis angry reaction(surprise).4 You ought to feel no(ashamed) about askingfor help5 They(pride) carried their country's flag6 My sister was(annoy) late.7 He didn't try to hide his(happy) - he just cried WILL MARK BRAINLIEST Give the reason why tho following is not a polynomial x^2-3x^-1+5The three is negativeAll exponents are not whole numbersThere are only three termsThe highest exponent is 2 Divido 63ml into2:3:4Ratio Trey deposits $700 into an account that pays simple interest at a rate of 6% per year. How much interest will he be paid in the first 3 years? Help pls! 37 points. For the function y = -7x, complete the following table. Please I need help with this question (see image).Show workings where necessary. Brenda wants to find the amount of dividend pald to the shareholders by JSL Inc. In which statement will JSL Inc. specifically show the dividendspald to shareholders?OAtrial balanceOB. balance sheet.Income statementODstatement of retained earningscash flow statements What data do forecasters use to characterize storms while still over open water? choose the combination of factors that creates clear skies. humidity high or low air temperature warm or cold air pressure high or low Describe the solutions of each inequality in words:2m 6 What's 27.63 subtracted by 60 (1) In 1970, Victoria, Australia passed the first law worldwide making safety belts required for drivers and front-seat passengers. (2) By 1991, over 80 jurisdictions worldwide had followed suit with the United States joining in 1984. (3) Like all new things, the law was first met with ridicule and scorn. (4) Opponents claimed that it was an unwarranted intrusion by government into their personal lives and that it denied people the right to determine their own safety and health standards. (5) However, numerous reports have proved that the laws are necessary to save lives. (6) A study conducted in 1998 for National Highway Traffic Safety Administration (NHTSA) called the Motor Vehicle Occupant Safety Survey (MVOSS) revealed that "80 percent of the respondents use [safety belts] because doing so is required by law." (7) Considering that seat belts have saved over 135,000 lives between 1975 and 2001 imagine how high the death toll would be if seat belts were NOT required by law. (8) A statistical analysis conducted by the NHTSA says, an estimated 5,500 lives could be saved each year by increasing the level of safety belt use in the United States to 90 percent." (9) Currently, only 68 percent of Americans wear safety belts.3Which phrase in sentence 2 should be placed in parentheses? A. suit with the United States joining B. jurisdictions worldwide C. with the United States joining in 1984 D. had followed suit Please help if you know please and thanks ;) What childhood challenges does Jacqueline remember how was family life like before the invention of the radio?