General Gravity Problem

Q.

A player throws a ball upwards with an initial speed of $29.4m{s}^{-1}$.
(a) What is the direction of acceleration during the upward motion of the ball?
(b) What are the velocity and acceleration of the ball at the highest point of its motion?
(c) Choose the x = 0 m and t = 0 s to be the location and time of the ball at its highest point, vertically downward direction to be the positive direction of x-axis, and give the signs of position, velocity and acceleration of the ball during its upward, and downward motion.
(d) To what height does the ball rise and after how long does the ball return to the player’s hands? (Take g = $9.8m{s}^{-2}$ and neglect air resistance).

Q.

A stone is thrown vertically upward with an initial velocity of $40m/s.$ Taking $g=10m/s^2$, find the maximum height reached by the stone. What is the net displacement and the total distance covered by the stone when the stone returns to ground?

Q.

A ball is thrown vertically upwards from the top of a tower at 4.9 m/s. It strikes the pond near the base of the tower after 3 seconds. The height of the tower is

1. 73.5 m
2. None of these
3. 44.1 m
4. 29.4 m

Q. A man in a balloon rising vertically with an acceleration of 4.9 m/$s^2$ releases a ball 2 sec after the balloon is let go from the ground. The greatest height above the ground reached by the ball is (g=9.8m/$s^2$)

1. 19.6 m
2. 9.8 m
3. 24.5 m
4. 14.7 m

Q. A ball is dropped from the top of a tower $120\text{m}$ high and simultaneously another ball is projected vertically upwards from the ground with a speed of $30\text{m/s}$. The two balls will meet after

1. $3\text{s}$
2. $4\text{s}$
3. $5\text{s}$
4. $2\text{s}$

Q. A parachutist after bailing out falls 50m without friction. When parachute opens, it decelerates at 2 m/$s^2$. He reaches the ground with a speed of 3ms. At what height, did he bail out ?

1. 91 m
2. 293 m
3. 111 m
4. 182 m

Q.

A parachutist drops first freely from an aeroplane for 10s and then parachute opens out. Now he descends with a net retardation of 2.5 m/ $s^2$. If he falls out of the plane at a height of 2495 m and g=10 m/$s^2$, his velocity on reaching the ground will be

1. 10 m/s

2. 15 m/s

3. 5 m/s

4. 20 m/s

Q. A frictionless wire AB is fixed on a sphere of radius R. A very small spherical ball slips on this wire. The time taken by this ball to slip from A to B is

1. 
2. 
3. 
4. 

Q.

To test the quality of a tennis ball, you drop it onto the floor from a height of 4.00 m. It rebounds to a height of 2.00 m. If the ball is in contact with the floor for 12.0ms, then what is the average acceleration during that contact?

1. - 1.26 × 10³ m/s²

2. + 10 m/s²

3. - 10 m/s²

4. + 1.26 × 10³ m/s²

Q. A parachutist after bailing out falls 50 m without friction. When parachute opens, it decelerates at 2$m/s^2$. He reaches the ground with a speed of 3 m/s . At what height, did he bail out ?

1. 293 m
2. 182 m
3. 111 m
4. 91 m

Q.

A balloon is at a height of 81 m and is ascending upwards with a velocity of $12\frac{m}{s}$. A body of 2kg weight is dropped from it. If $g=10\frac{m}{s^2}$, the body will reach the surface of the earth in

A. 4.025 s

B. 5.4 s

C. 6.75 s

D. 1.5 s

Q.

a body slides down from rest from the top of 6.4m long rough plane inclined at 30degree with the horizontal find the time taken by block in reaching the bottom of the plane Take coefficient of friction to be 0.2 and g=9.8m/s^2

Q. A rocket is fired upward from the earth's surface such that it creates an acceleration of 19.6$m/se{c}^2$. If after 5 sec its engine is switched off, the maximum height of the rocket from earth's surface would be

1. 980 m
2. 735 m
3. 245 m
4. 490 m

Q. A balloon is rising vertically up with a velocity of 29$m{s}^{-1}$. A stone is dropped from it and it reaches the ground in 10 seconds. The height of the balloon when the stone was dropped from it is$(g=9.8m{s}^{-2})$

1. 150 m
2. 100 m
3. 200 m
4. 400 m

Q. A stone dropped from a building of height h and it reaches after t seconds on earth. From the same building if two stones are thrown (one upwards and other downwards) with the same velocity u and they reach the earth surface after $t_1$ and$t_2$ seconds respectively, then

1. $t=t_1-t_2$
2. $t=\frac{t_1+t_2}{2}$
3. $t=\sqrt{t_1{t}_2}$
4. $t=t_1^2{t}_2^2$

Q. Which Indian scientist is popularly known as missile man of India?

1. Dr. A. P. J. Abdul Kalam
2. Dr. C .V. Raman
3. Dr. Har Gobind Khorana
4. None of the above

Q. A lift is moving up with acceleration a. A person inside the lift throws the ball upwards with a velocity u relative to hand. What is the maximum height reached by the ball in the lift?

1. $\frac{u^2}{2(g+a)}$
2. $\frac{u}{2(g+a)}$
3. $\frac{u^2}{(g+a)}$
4. $\frac{u}{(g+a)}$

Q. A ball is dropped on the floor from a height of 10 m. It rebounds to a height of 2.5 m. If the ball is in contact with the floor for 0.01 sec, the average acceleration during contact is

1. 
2. 
3. 
4. 

Q. A stone dropped from a building of height h and it reaches after t seconds on earth. From the same building if two stones are thrown (one upwards and other downwards) with the same velocity u and they reach the earth surface after $t_1$ and$t_2$ seconds respectively, then

1. 
2. t = t₁ - t₂
3. 
4. 

Q.

A ball is thrown up from the top of a tower at 20 m/s velocity. It took the ball 6 sec to fall to the bottom. For how long was the ball above the tower?

1. 2 sec

2. 4 sec

3. 6 sec

4. 1 sec

Q. A man drops a ball downside from the roof of a tower of height 400 meters. At the same time another ball is thrown upside with a velocity $50\frac{meter}{sec}$. from the bottom of the tower, then they will meet at which height from the bottom of the tower

1. 100 meters
2. 320 meters
3. 80 meters
4. 240 meters

Q. A block of wood floats in a bucket of water placed in a lift. Will the block sink more or less if the lift starts accelerating up?

Q. A body is projected vertically upward with a speed $40$ meter per second. The distance travelled by the body in the last second of upward journey is?

1. $4.9m$
2. $9.8m$
3. $12.4m$
4. $19.6m$

Q. A bird is flying 3m above the surface of water. To a fish underwater, the height of the bird from the water surface appears to be [Take ${\mu }_w=4/3$]

1. $2m$
2. $3.33m$
3. $4m$
4. $\left(4/3\right)m$

Q. A ball is droped from a high rise platform $t=0$ starting from rest. After $6s$ another ball is thrown downwards from the same platform with a speed $v$. The two balls meet at $t=18s$. What is the value of $v$?

1. 75 m/s
2. 94 m/s
3. 64 m/s
4. 84 m/s

Q. A small spherical ball of mass $m$ slides without friction from the top of a hemisphere of radius $R$. At what height will the ball lose contact with surface of the sphere?

Q. A man in a ballon rising vertically with an acceleration of $4.9\frac{m}{se{c}^2}$ releases a ball 2 sec after the balloon is let go from the ground. The greatest height above the ground reached by the ball is $(g=\frac{9.8m}{se{c}^2})$

1. 14.7 m
2. 19.6 m
3. 9.8 m
4. 24.5 m

Q. A stone is dropped into water from a bridge 44.1m above the water. Another stone is thrown vertically downward 1 sec later. Both strike the water simultaneously. What was the initial speed of the second stone

1. 12.25 m/s
2. 14.75 m/s
3. 16.23 m/s
4. 17.15 m/s

Q.

A body A is projected upwards with a velocity of 98 m/s. The second body B is projected upwards with the same initial velocity but after 4 sec. Both the bodies will meet after

1. 6 sec

2. 8 sec

3. 10 sec

4. 12 sec

Q. A source of the sound of frequency. $256Hz$ is moving rapidly towards a wall with a speed of $5m/s$. How many beats per second will be heard If sound travels at a speed of $330m/s$?