Freefall & Motion

Q.

What type of motion, uniform or non-uniform, is exhibited by a freely falling body? Give reason for your answer.

Q.

What do you mean by free fall?

Q.

The value of acceleration due to gravity:

1. is same on the equator and the poles

2. is least on the poles

3. is least on the equator

4. increases from pole to equator

Q.

Give some examples of uniform accelerated motion?

Q.

A freely falling object travels 4.9 m in 1st second, 14.7 m in 2nd second, 24.5 m in 3rd second, and so on. This data shows that the motion of a freely falling object is a case of :

(a) uniform motion (b) uniform acceleration

(c) no acceleration (d) uniform velocity

Q.

What type of motion is exhibited by a freely falling body?

Q. A 500kg rocket is fired straight up from the earth, the engines provide 7500 newtons of thrust. Its acceleration is

Q.

Explain why the value of $g$ differs while moving from poles to the equator on the surface of the earth. State how would its value change on moving towards the center of the earth.

Q. A stone is dropped from a tower of height $100\text{m}$. At the same time, another stone is thrown upwards at a speed of $25\text{m}{\text{s}}^{-1}$. When and where the two stones would meet? Take $\text{g}=10\text{m}{\text{s}}^{-2}$

1. Time $=4\text{s}$ ; Height $=80\text{m}$
2. Time $=6\text{s}$ ; Height $=50\text{m}$
3. Time $=7.5\text{s}$ ; Height $=100\text{m}$
4. Time $=2.5\text{s}$ ; Height $=40\text{m}$

Q.

What is the acceleration of freely falling body?

1. $0$

2. $1m{s}^{-2}$

3. $10m{s}^{-2}$

4. $9.8m{s}^{-2}$

Q.

Two objects of different masses falling freely near the surface of Moon from same height would

1. have same velocities at any instant.

2. have different accelerations.

3. experience forces of same magnitude.

4. The same acceleration due to gravity of Moon is applied on both the objects.

Q.

Why is the value of $g$ minimum at the equator?

Q.

A ball thrown up vertically returns to the thrower after 6 s. The velocity with which it was thrown up is (Take $g=9.8m{s}^{-2}$)

1. $24.9m{s}^{-1}$

2. $29.4m{s}^{-1}$

3. $39.4m{s}^{-1}$

4. $34.9m{s}^{-1}$

Q.

A ball is thrown straight up. The magnitude of acceleration at the top point on its path is

1. $g$

2. $\frac{g}{2}$

3. zero

4. $\frac{2g}{3}$

Q.

If you drop a stone and a piece of paper to the earth, they don't take the same time to reach the earth because:

1. acceleration due to gravity is more for the stone

2. air resistance slows down the paper more.

3. mass of stone is more than mass of paper

4. universal gravitational constant G is different for both

Q.

How can the motion of a freely falling body be an example for uniformly accelerated motion?

Q. A ball is thrown upwards with a velocity of $10m{s}^{-1}$. Find the maximum height reached by the ball. Take acceleration due to gravity $g=10{ms}^{-2}$.

1. $13m$

2. $5m$

3. $15m$

4. $16m$

Q.

A balloon is going upwards with a velocity of $12m/s$. It releases a packet when it is at a height of $65m$ from the ground. How much time will the packet take to reach the ground if $g=10m/s^2$?

Q.

A ball is thrown vertically upwards at speed of $20m{s}^{-1}$. Find the time taken by the ball to reach back to the original position. [Take acceleration die to gravity, $g=10m{s}^{-2}$]

1. $6s$

2. $4s$

3. $3s$

4. $10s$

Q.

How does the acceleration due to gravity vary from place to place on the surface of the Earth?

Q. A Particle projected vertically upward passes the same height h at 2s and at 10s.If the acceleration due to gravity g=9.8 m/s^2, then what is the height?

Q.

A ball of radius r and density Ρ falls freely under gravity through a distance h before entering water. Velocity of ball does not change even on entering water. If viscosity of water is h, the value of h is given by

1. 
2. 
3. 
4. 

Q.

1. State which of the following situations are possible and give an example of each of these:-
   1. a body moving with constant acceleration but with zero velocity.
   2. A body moving horizontally with acceleration in vertical direction.
   3. A body moving with a constant speed in an accelerated motion.

Q. The value of the acceleration due to gravity for a body thrown upward will be.

1. zero
2. negative
3. positive

Q. The velocity of a freely falling body, starting at rest and after one second is ___.(Round your answer to the nearest integer ; Choose all that apply )

1. 10 m/sec
2. 36 km/hr
3. 1 km/sec
4. 100 cm/sec

Q.

If an object is thrown in upward direction, then the gravitational acceleration is positive.

1. True
2. False

Q.

A car falls off an edge and drops to the ground in 0.5 seconds. What is its speed on striking the ground? (Take g = 10 $m{s}^{-2}$)

1. 5 $m{s}^{-1}$

2. 1 $m{s}^{-1}$

3. 3 $m{s}^{-1}$

4. 4 $m{s}^{-1}$

Q.

Why does a gun recoil when a bullet is fired ? Explain recoil?

Q.

A body falls freely from a height of $490m$. Determine the displacement of the body during the last second of its descent.

Q.

Is$g$ vector or scalar? Write its SI unit.