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

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.

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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

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;

Substituting into the equation, we have;

XL = 120/2.4

XL = 50.00 ohms

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

Answer:

it is A or D

Explanation:

Answer:

ANswer:A

Explanation:

Answer:

its true!!

Explanation: have a nice day !!

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.

Answer:

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

Explanation:

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

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

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.

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 .

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 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]

[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.

Answer:

D-Enhancing memory

Explanation:

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