Mechanics | Relativity Answers

Q1. For the shaded area shown in figure. Determine:-Co-ordinates of centroid

The removed area is semi-circle and all the given dimensions are in cm. Dimension of rectangle is 12.5*20 cm² and diameter of semi-circle is 7.5 cm.

12.5

7.5

1. A man is standing on the edge of a 20.0 m high cliff. He throws a rock vertically with an initial velocity of

10.0 m/s. How long does it take to reach its max height?

2. A coin is dropped in a vacuum tube, find its displacement after 0.30 seconds.

3. An object dropped on planet X falls 64 m in 4 seconds. Find the acceleration due to gravity on planet X.

4. A basketball player jumped straight up to grab a rebound. If she was in the air for 0.80 seconds, how

high did he jump?

5. A ball drops from a tall building. The ball strikes the sidewalk 2.0 seconds later. What is the velocity of

the ball when it hits the sidewalk?

6. A stone is thrown vertically upward with a speed of 12.0 m/s from the edge of a cliff 70.0 m high. How

long does it take to reach the bottom of the cliff?

7. An object initially at rest falls freely near Earth's surface. How long does it take the object to attain a

speed of 200 m/s?

8. What is the velocity of an object that has been falling freely in a vacuum for 2 seconds?

Say mr karim runs on a plain land and jumps from a spot in forward direction. Recognize and describe his jumping motion through an equation and make an argument for your answer.

One day a teen boy went out of their house and stood beside a pond.He threw a small rock in the pond relatively far from him and found that a nice wave was coming toward him.He felt a lovely moment.He threw another similar stone in the pond relatively close to him.He found that the first wave was distributed and was not coming to him smoothly. He tried to understand, 'Why did it happen? 'But failed and become unhappy. How will you explain this incidence in details to the boy to make him so happy?Please mention the principle involved in the incident and explain different case of its applications.

Miss Y agreed to keep a request from her friend to cook rice in an aluminium pot. A metal cover was used on the top of the aluminium pot during cooking, but after a short-while the metal cover was fallen down. They involved in a debate to explain it using a theorem of physics why the metal cover has been fallen down from the top of the aluminium pot. Miss Y said that it was due to produced pressure but her friend agreed on it to some extent and also asked about the conversion of energy, demanding to show the expression for the theorem. Could please help Miss Y?

3. One day a teen boy went out of their house and stood beside a pond. He threw a small rock in

the pond relatively far from him and found that a nice wave was coming toward him. He felt a

lovely moment. He threw another similar stone in the pond relatively close to him. He found

that the first wave was disturbed and was not coming to him smoothly. He tried to understand,

‘why did it happen?’ but failed and become unhappy. How will you explain this incidence in

details to the boy to make him so happy? Please mention the principle involved in the incident

and explain different cases of its applications.

An asteroid woth mass = 1.00 x 109 kg comes from deep space, effectively from infinity, falls toward the Earth.

Find the change in potential energy when it reaches a point 4.00 x 108 m from the center of the earth. In addition find the work done by the force of gravity.

Solar ponds are small artificial lakes of a few meters deep that are

used to store solar energy. The rise of heated (and thus less dense)

water to the surface is prevented by adding salt at the pond bottom.

In a typical salt gradient solar pond, the density of water increases in

the gradient zone, as shown in Fig. 1–52, and the density can be

expressed as

where ρ° is the density on the water surface, s is the vertical distance

measured downward from the top of the gradient zone (s 5 2z), and

H is the thickness of the gradient zone. For H 5 4 m, r0 5 1040 kg/m3,

and a thickness of 0.8 m for the surface zone, calculate the gage

pressure at the bottom of the gradient zone

Find the total work done in moving a particle in a force field given by F=3xyi-5zj+10xk along the curve x=t^2+1, y=2t^2, z=t^3 from t=1 to t=2.

Why it's that the engine of a car is always at the bottom but not at top of the car