Answer:
the velocity of a moving body relative to another body is called relative velocity.
Thurst exerted by an object of area20m² experiencing pressure 150 Nm‐² is ________
Answer:
3000 N
Explanation:
as we know that
pressure=force/area
so force=thurst
pressure=thurst/area
thyrst=pressure*area
pressure=150 Nm^-2
area=20m^2
so thurst=150*20=3000 N or 3*10^3 N
Suppose a current-carrying wire has a cross-sectional area that gradually becomes smaller along the wire, so that the wire has the shape of a very long,truncated cone. How does the drift speed vary along the wire?
Answer:
It slows down as the cross-section becomes smaller is the correct answer to this question.
Explanation:
That current is the same in all parts of the wire under steady-state conditions.Thus the velocity of drift is approximately equal to the cross‐sectional region.vd = I /nAq . As the cross-section gets smaller it accelerates.Which of these are scientific questions? Check all that apply. How will climate change affect forests? Which planet is the prettiest? How did life on Earth begin? Why did dinosaurs go extinct? Which volcano is the most amazing?
Answer:
The scientific questions here are:
a) How will climate change affect forests
b) How did life on Earth begin
c) Why did dinosaurs go extinct
Explanation:
Scientific question are logical quantifiable questions, whose answers can be measured. A good scientific question must have answers that can be tested by a carefully designed experiment or measurement. Some qualities like "prettiest" and "amazing" cannot be tested for nor are they measurable, and hence, they do not make a testable component of good scientific question.
Suppose the maximum safe intensity of microwaves for human exposure is taken to be 1.00 W/m2. (a) If a radar unit leaks 50.0 W of microwaves (other than those sent by its antenna) uniformly in all directions, how far away (in cm) must you be to be exposed to an intensity considered to be safe
Answer:
The safe distance is 199 cm approximately 200 cm
Explanation:
Safe intensity = 1.00 W/m^2
wattage of radar leaked radar = 50.0 W
safe distance from the microwave will be = ?
We know that the intensity of a wave radiated uniformly in all direction is given as
[tex]I[/tex] = [tex]\frac{W}{A}[/tex]
where
W is the wattage of the leaked radar
A is the radial area, which is the area of a sphere that encapsulates the region through which this wave spreads uniformly.
From the equation above,
[tex]A[/tex] = [tex]\frac{W}{I}[/tex] = 50/1 = 50 m^2
But the area of this sphere [tex]A[/tex] = [tex]4\pi r^{2}[/tex]
where
r is the safe distance from the radar source
substituting for the area, we have
50 = 4 x 3.142 x [tex]r^{2}[/tex]
50 = 12.568 [tex]r^{2}[/tex]
[tex]r^{2}[/tex] = 50/12.568 = 3.978
r = [tex]\sqrt{3.978}[/tex] = 1.99 m = 199 cm ≅ 200 cm
A ball is thrown vertically upwards. It returns 6s later. Calculate : (1) the greatest height reached by the ball, and (2) the initial velocity of the ball. (Take g=9.8m/s2)
Answer:
greatest displacement = 44.1m
initial velocity= 29.4m/s
Explanation:
Greatest displacement
s=1/2at^2
= (9.8/2 ×9)m
= 44.1m
initial velocity
s=ut-1/2at^2
44.1= 3u -(1/2×9.8×9)
44.1=3u-44.1
3u=88.2
u=29.4m/s
On his fishing trip Justin rides in a boat 12 km south. The fish aren’t biting so they go 4 km west. They then follow a school of fish 1 km north. What distance did they cover? What was their displacement?
Answer:
I think the answer is 8km2
Answer:
Distance = 17km
Displacement = 12.6 km
Explanation:
south 12km
west 4km
north 1km
Total distance = 12 + 4 + 1 = 17km
Total displacement = in picture above.
A polonium isotope with an atomic mass of 211.988868 u undergoes alpha decay, resulting in a daughter isotope with an atomic mass of 207.976652 u. Ignoring any recoil of the daughter, find the kinetic energy of the emitted alpha particle in megaelectronvolts (MeV).
Answer:
K = 9.53 MeV
Explanation:
The kinetic energy that the alpha particle has emitted, is the energy in excess after removing the resting energy of the atoms and the helium nucleus that forms the alpha particle
Since energy and masses are related and cannot be
m₀ c² = [tex]m_{f}[/tex] c² + m_He c²+ K
K = c² (m₀ - m_{f} - m_He)
the mass of the Helium atom is 4 u
K = (3 10⁸)² (211,988868 -207.976652 - 4,002) 1,661 10⁻²⁷
K = 14,949 10⁻¹¹ (0.0102)
K = 1,527 10⁻¹² J
let's reduce 1 J = 6,242 10¹² MeV
K = 9.53 MeV
The robot HooRU is lost in space, floating around aimlessly, and radiates heat into the depths of the cosmos at the rate of 13.5 W. HooRU's surface area is 1.51 m^2 and the emissivity of its surface is 0.209. Ignore the radiation HooRU absorbs from the cold universe. What is HooRU's temperature?
Answer:
165.73 K
Explanation:
The computation of HooRU's temperature is shown below:-
As per the stefan's law, the power radiated by black body radiations which is
[tex]P = eA\sigma T^4[/tex]
where
A indicates surface area
e indicates emissitivity
T indicates temperature
now, we will put the values in the above equation
[tex]13.5 = 0.209 \times 1.51 \times \sigma \times T^4[/tex]
After solving the above equation we will get temperature which results
= 165.73 K
Therefore for computing the HooRU's temperature we simply applied the above formula.
A rocket moves through empty space in a straight line with constant speed. It is very far from any star or planet. Under these conditions, the force that must be applied to the rocket in order to sustain its motion is
Answer:
analysis the force is zero
Explanation:
Let's apply Newton's second law
F = m a
In this equation we see that the force is directly related to the acceleration, as they indicate that the rocket is far from any planet or star has no force applied to it, therefore they also relate it to zero.
Change we can analyze the exercise with Newton's first law, which indicates that an object maintains its constant speed in a straight line has no forces applied to it.
In either analysis the force is zero
3.27 moles of an ideal gas has a pressure of 125000 Pa at 15.0 ° C What is the volume of the gas?
Answer:
15.96 m³ (corrected to 2 d.p.)
Explanation:
Using idea gas law:
pV = nRT
pressure p = 125000 Pa
volume V = unknown
no. of moles n= 3.27 moles
ideal gas constant R = 8.3145 J K−1 mol−1
Temperature t (in Kelvins) = 15 + 273.15 = 288.15K
125000 x v = 3.27 x 8.3145 x 288.15
v = 15.96 m³ (corrected to 2 d.p.)
Answer:
0.0626 m^3
Explanation:
First, we know that the equation to calculate the behavior of gases is:
PV=nRT
Looking at the problem, we understand that we are needing to solve for V, which means we need to isolate V to solve for it.
The new equation will look something like this:
V=nRT/P
The last step is to simply plug in the remaining variables:
n=3.27
R=8.31 (that is not given but is a standard number that you will always use for "R"/ the ideal gas constant-it helps to right it down somewhere to reference it if you ever need it!)
P=125000
T=288 (the temp needs to be in degrees K, so take 15.0 degrees c and + 273)
Finally, when you input all of those, you will have something that looks like this:
V=(3.27*8.31*288)/125000
V=0.02608205 m^3
V= 0.0626 m^3 (rounded to 3 sig. figs)
I hope this was helpful and easy to understand!
A vertical bar consists of three prismatic segments A1, A2, and A3 with cross-sectional areas of 6000 mm2 , 5000 mm2 , and 4000 mm2 , respectively. The bar is made of steel with E 5 200 GPa. Calculate the displacements at points B, D
Answer and Explanation:
For computing the displacement at point B and D we need to determine the following calculations
[tex]P_Net = P_C + P_E + P_B[/tex]
= 250 + 350 - 50
= 550 N
Now the deflection for bar AB is
[tex]\delta_{AB} = \frac{PL_{AB}}{AE} \\\\ = \frac{550 \times 500}{6,000 \times 200 \times 10^{3}}[/tex]
[tex]= 2.292 \times 10^{-4} mm[/tex]Now for bar BC it is
[tex]\delta_{BC} = \frac{PL_{BC}}{AE} \\\\ = \frac{(550 + 50) \times 250}{5,000 \times 200 \times 10^{3}} \\\\ = 1.5 \times 10^{-04} mm[/tex]
And for bar CD it is
[tex]\delta_{CD} = \frac{PL_{CD}}{AE} \\\\ = \frac{(550 -250 + 50) \times 250}{5,000 \times 200 \times 10^{3}} \\\\ = 0.875 \times 10^{-4} mm[/tex]
Now the displacement is as follows
For B
2.292 × 10^{-4} mm
For D, it is
[tex]= 2.292 \times 10^{-4} + 1.5 \times 10^{-4} + 0.875 \times 10^{-4} mm \\\\ = 4.667 \times 10^{-4} mm[/tex]
We simply applied the above formulas for determining the displacements at points B, D and the same is to be considered
please help me with this question
Car at rest:
velocity= 0m/s
Acceleration:
0.2m/s²
Since total time:
3 min = 180s
Formula of acceleration:
acceleration = [final velocity - initial velocity] ÷ [total time]
Velocity at end:
0.2m/s² = [final velocity - 0m/s] ÷ [180s]
0.2m/s² × 180s = [final velocity]
[final velocity] = 36m/s
Distance travelled:
Velocity = displacement(distance) ÷ time
36m/s = displacement(distance) ÷ 180s
displacement(distance) = 36m/s × 180s
displacement(distance) = 6480m
Hey I'm sorry but i do not understand why the answer on your worksheet for distance travelled is 3240m... its half of what my answer is...
5. i) Name two devices based on interaction between magnetic field and current carrying conductor.
Answer:
some common devices that use current carrying conductors and magnetic fields are electric motor electric generator loudspeakers microphones and measuring instruments like galvanometer ammeter and voltmeter
Earthquakes at fault lines in Earth's crust create seismic waves, which are longitudinal (P-waves) or transverse (S-waves). The P-waves have a speed of about 9 km/s. Estimate the average bulk modulus of Earth's crust given that the density of rock is about 2500 kg/m3
Answer:
[tex]B=2.025\times 10^{11}\ Pa[/tex]
Explanation:
It is given that,
Speed of P- waves, v = 9 km/s = 9000 m/s
The density of rock is about [tex]2500\ kg/m^3[/tex]
We need to find the average bulk modulus of Earth's crust. Let it is given by B. So,
[tex]v=\sqrt{\dfrac{B}{d}} \\\\B=v^2d\\\\B=(9000)^2\times 2500\\\\B=2.025\times 10^{11}\ Pa[/tex]
So, the bulk modulus of the Earth's crust is [tex]2.025\times 10^{11}\ Pa[/tex].
4. Going back to the dog whistle in question 1, what is the minimum riding speed needed to be able to hear the whistle? Remember, you can assume the following things: The whistle you use to call your hunting dog has a frequency of 21.0 kHz, but your dog is ignoring it. You suspect the whistle may not be working, but you can't hear sounds above 20.0 kHz. The speed of sound is 330 m/s at the current air temperature.
Answer:
The minimum riding speed relative to the whistle (stationary) to be able to hear the sound at 21.0 kHz frequency is 15.7 m/s
Explanation:
The Doppler shift equation is given as follows;
[tex]f' = \dfrac{v - v_o}{v + v_s} \times f[/tex]
Where:
f' = Required observed frequency = 20.0 kHz
f = Real frequency = 21.0 kHz
v = Sound wave velocity = 330 m/s
[tex]v_o[/tex] = Observer velocity = X m/s
[tex]v_s[/tex] = Source velocity = 0 m/s (Assuming the source is stationary)
Which gives;
[tex]20 = \dfrac{330- v_o}{330+0} \times 21[/tex]
330 - [tex]v_o[/tex] = (20/21)*330
[tex]v_o[/tex] = 330 - (20/21)*330 = 15.7 m/s
The minimum riding speed relative to the whistle (stationary) to be able to hear the sound at 21.0 kHz frequency = 15.7 m/s.
The water tank is kept at some height of the buildings. Why?
Answer:
The water is at the top because when the water is stored at the top it does not need as much energy to get it to flow because it will be flowing down and be affected by gravity to make the water pressure.
Answer:
The water is at the top because when the water is stored at the top it does not need as much energy to get it to flow because it will be flowing down and be affected by gravity to make the water pressure.
Explanation:
Signal propagation in the nervous system can be modeled as
a) A resistor network.
b) A wave of electricity that travels down conducting tissue.
c) A series of RC circuits.
Answer:
c) A series of RC circuits.
This mathematical model describes the changes that occur in a sample of
water as its temperature increases. Use this model to predict what will
happen to the motion of the molecules in a sample of water that is being
heated from 50° to 100°C.
200°C
vaporization
150°C
melting
100°C
Temperature (°C)
water vapor
50°C
liquid water
0°C-
--50°C
10
20
ice
30
Time (min)
40
50
60
70
O A. The motion will change very little.
O B. The molecules will stop moving.
O C. The movement of the molecules will gradually decrease.
O D. The movement of the molecules will gradually increase.
The correct answer is D. The movement of the molecules will gradually increase.
Explanation:
At the beginning of the model the state of matter of the water is solid, in this, particles have a defined arrangement and are together, which stops particles from moving freely and only allows them to vibrate. However, as the substance is heated the thermal energy (heat) increases in the sample, this causes particles to move more and the arrangement of it changes. Due to this, when the ice melts and there is liquid water particles move more than in solid states, which makes ice lacks a defined shape. Moreover, as the heat continues to increase the thermal and kinetic energy (movement) increases, indeed in gas state (water vapor) particles will move freely. This means the movement or kinetic energy in particles gradually increases in the model.
Answer: D
Explanation:
Neglecting air resistance, the distance s(t) in feet traveled by a freely falling object is given by the function s(t)=16t2, where t is time in seconds. The height of a certain tower is 840 feet. How long would it take an object to fall to the ground from the top of the building?
Answer:
t=7.25 sec
Explanation:
840=16t'2,
If you precisely measure the position of a particle, you __________. If you precisely measure the position of a particle, you __________. destroy information about its momentum convert it into a wave cause it to interfere cause the particle to be annihilated
Answer:
Destroy information about the speed of the particle
Explanation:
This is according to Heisenberg's Uncertainty Principle states that there is inherent uncertainty in the act of measuring a variable of a particle. Commonly applied to the position and momentum of a particle, the principle states that the more precisely the position is known the more uncertain the momentum is and vice versa.
# A cheetah can start from rest and attain the velocity 72km/h in 2 seconds. Calculate the acceleration of cheetah
Answer:
[tex]10 \: [/tex] m/s ^2Explanation:
Solution,
When a certain object comes in motion from rest, in the case, initial velocity = 0 m/s
Initial velocity ( u ) = 0 m/s
Final velocity ( v ) = 72 km/h ( Given)
We have to convert 72 km /h in m/s
[tex]72 \: km \: per \: hour[/tex]
[tex] = 72 \times \frac{1000}{60 \times 60} [/tex]
[tex] = 20 [/tex] m/s
Final velocity ( v ) = 20 m/s
Time taken ( t ) = 2 seconds
Acceleration (a) = ?
Now,
we have,
[tex]a = \frac{v - u}{t} [/tex]
[tex]a = \frac{20 - 0}{2} [/tex]
[tex]a = \frac{20}{2} [/tex]
[tex]a = 10 [/tex] m/s ^2
Hope this helps...
Good luck on your assignment..
A truck is moving with a certain uniform velocity. It is accelerated uniformly by 0.75 m/s^2. After 20 seconds , the velocity becomes 72km/h.Find the initial velocity
Answer:
Vi = 5 m/s
Explanation:
let (a) acceleration = 0.75 m/s²
(t) time = 20 seconds
Vf = final velocity = 72 km/hr (convert to m/s to units consistency = 20 m/s)
find Initial velocity (Vi)
Vf - Vi
a = -----------
t
Vi = Vf - (a * t) = 20 - (0.75 * 20)
Vi = 5 m/s
PLEASE HELP!!!! i will give brainliest to the first person...
Answer: Fossil fuels power the machine that shakes the tree so the apples fall to the ground
Explanation: most machines are powered by fossil fuels
Two large rectangular aluminum plates of area 180 cm2 face each other with a separation of 3 mm between them. The plates are charged with equal amount of opposite charges, ±17 µC. The charges on the plates face each other. Find the flux (in N · m2/C) through a circle of radius 3.5 cm between the plates when the normal to the circle makes an angle of 4° with a line perpendicular to the plates. Note that this angle can also be given as 180° + 4°.
Answer:
Electric flux;
Φ = 30.095 × 10⁴ N.m²/C
Explanation:
We are given;
Charge on plate; q = 17 µC = 17 × 10^(-6) C
Area of the plates; A_p = 180 cm² = 180 × 10^(-4) m²
Angle between the normal of the area and electric field; θ = 4°
Radius;r = 3 cm = 3 × 10^(-2) m = 0.03 m
Permittivity of free space;ε_o = 8.85 × 10^(-12) C²/N.m²
The charge density on the plate is given by the formula;
σ = q/A_p
Thus;
σ = (17 × 10^(-6))/(180 × 10^(-4))
σ = 0.944 × 10^(-3) C/m²
Also, the electric field is given by the formula;
E = σ/ε_o
E = (0.944 × 10^(-3))/(8.85 × 10^(-12))
E = 1.067 × 10^(8) N/C
Now, the formula for electric flux for uniform electric field is given as;
Φ = EAcos θ
Where A = πr² = π × 0.03² = 9π × 10^(-4) m²
Thus;
Φ = 1.067 × 10^(8) × 9π × 10^(-4) × cos 4
Φ = 30.095 × 10⁴ N.m²/C
Read the excerpt from "Justin Lebo.” When he got it home, he wheeled the junker into the garage and showed it proudly to his father. "Will you help me fix it up?" he asked. Justin's hobby was bike racing, a passion the two of them shared. Their garage barely had room for the car anymore. It was more like a bike shop. Tires and frames hung from hooks on the ceiling, and bike wrenches dangled from the walls. Based on the details in this excerpt, which word best describes the garage? inviting dangerous cluttered sparse
Answer:
cluttered
Explanation:
The correct word to describe the garage would be cluttered.
A place is said to be cluttered when it is filled with an untidy collection of material things. In this case, the garage is filled with materials such as bike wrenches, tires, frames, etc.
Inviting can also mean tempting, attractive, etc, and has no relevance to the condition of the garage as described in the excerpt.
Dangerous can also mean harmful, and not the right word to describe the garage.
Sparse can also mean scanty, scattered, and would be the opposite of the condition of the garage.
Correct answer: cluttered
Answer:
c. cluttered
Explanation:
A rocket is launched vertically from the ground with an initial velocity of 64. Write a quadratic function that shows the height, in feet, of the rocket t seconds after it was launched.
Answer:
y = 64t − 16t²
Explanation:
y = y₀ + v₀ t + ½ at²
y = 0 + 64 t + ½ (-32) t²
y = 64t − 16t²
A ball is dropped from a height of 20m. If its velocity increases uniformly at the rate 10m/s2 with what velocity and after what time will it strike the ground?
Answer: 2 seconds
Explanation:
Since I've only memorized a couple of formulas for these things, I need to do the time first:
I'll use the formula Distance = (1/2) (acceleration) (time)²
20 m = (1/2) (10 m/s²) (time)²
Time² = (20 m) / (5 m/s²)
Time² = 4 sec²
Time = 2 seconds
Now ...
-- When the ball hits the ground, it has been falling for 2 seconds.
-- Its acceleration has caused its speed to increase by 10 m/s every second.
-- So after 2 seconds, its speed has grown to (2 s) (10 m/s²) = 20 m/s .
3. An electron with a mass of 9.11 X 10^-31 kg is moving at a speed of 2.19 X 10 m/s. What is the kinetic energy of the electron?
Answer:
[tex] 2.18\times 10^{-30} \:J[/tex]
Explanation:
[tex] K.E._{Electron}= \frac{1}{2} mv^2 \\\\
= \frac{1}{2} \times 9.11\times 10^{-31}\times (2.19\times 10)^2 \\\\
=4.555\times 10^{-31}\times 4.7961\times 10^2 \\\\
=4.555\times 10^{-31+2}\times 4.7961 \\\\
=21.8462355\times 10^{-29}\\
=2.18462355\times 10^{-30}\\
=2.18\times 10^{-30} \:J\\[/tex]
Two runners start at a distance of 10 miles from each other. They run towards each other at a constant velocity of 5 mph. A fly takes off from runner one’s nose at time zero. The fly has a constant velocity of 20 mph and flies between the runners. Find the total distance that the fly has traveled when the runners collide.
Answer:
The fly will travel 20 miles before the runners collide with each other.
Explanation:
Since the runners are both traveling at the same speed, they will meet and collide in the exact middle of each other which is 5 miles away from their starting point. Since they are traveling at 5 mph, it will take exactly one hour before they collide. The fly is going 20 mph so it will travel 20 miles before the runners collide in one hour.
If you could travel from one planet to another
in our solar system, which of the following
would change the most?
A. your weight
B. your mass
C. your height
D. your width