Free Falling object

Q.

In vacuum, a freely falling body has ___.

1. same velocity

2. same acceleration

3. same speed

4. no net force

Q.

A man pushes a box of mass $50kg$ with a force of $80N$. What will be the acceleration of the box due to this force?

Q. If paper and stone are dropped from rest simultaneously from the top of a tower, which would reach the ground first? (Neglect air/atmosphere resistance)

1. Paper
2. Stone
3. Both will reach at the same time
4. Whichever has heavier mass

Q. If a hammer and a one rupee coin are dropped simultaneously from the top of a tower, which would reach the ground first? (Neglect air/atmosphere)

1. Coin
2. Both will reach at the same time
3. Insufficient information
4. Hammer

Q. An object is said to be in a state of free fall when:

1. The velocity of the body is constant.
2. It is accelerating towards the Earth.
3. The only force acting on it is the weight of the object.
4. It is moving towards Earth.

Q. The value of acceleration due to gravity decreases with increase in ___.

1. weight
2. horizontal displacement
3. momentum
4. altitude

Q.

What is the value of acceleration due to gravity of the Earth?
(Given mass of the Earth is $6\times {10}^{24}kg$ and radius of the Earth is $6.4\times$ ${10}^{6}m$).

1. $9.8m{s}^{-2}$
2. $9.8cm{s}^{-2}$
3. $9.8mm{s}^{-2}$
4. $9.8km{s}^{-2}$

Q. Find the acceleration due to gravity 'g' in terms of mean density of the Earth 'd'. Assume it to be a perfect sphere.

1. $\frac{4\pi r^2}{G}$
2. $4\pi r^{2}dG$​
3. $\frac{4\pi RdG}{3}$
4. $\frac{3}{4\pi RdG}$

Q. A student determined to test the law of gravity for himself walks off a sky scraper 320 m high with a stopwatch in hand and starts his free fall (zero initial velocity). 5 second later, superman arrives at the scene and dives off the roof to save the student. What must be the maximum height of the skyscraper so that even superman cannot save him.

1. 65 m
2. 85 m
3. 125 m
4. 145 m

Q. Find the acceleration due to gravity 'g' in terms of mean density of the Earth 'd'. Assume it to be a perfect sphere.

1. $4\pi r^{2}dG$​
2. $\frac{4\pi r^2}{G}$
3. $\frac{3}{4\pi RdG}$
4. $\frac{4\pi RdG}{3}$

Q. Identify the free fall situations from the following.

1. A man landing through a parachute
2. An apple falling on moon
3. A rocket propelling into space
4. A heavy stone falling from a cliff

Q. A person of weight $70kg$, a stone of weight $1kg$ and a paper of weight $10g$ start falling at the same time on the earth from a height of $100ft$. If the air resistance is neglected, which of the following will reach the earth first?

1. Person
2. Stone
3. Paper
4. All will reach the earth at the same time

Q. The force that acts vertically downwards on any body that has mass is called .

1. weight
2. magnetic force
3. frictional force

Q. An object is said to be in a state of free fall when:

1. It accelerates under the force of gravity.
2. The only force acting on it is the weight of the object.
3. Initial velocity is zero.
4. Object is moving towards Earth.