Freefall & Motion

Q.

Explain the phenomenon behind free fall.

Q. What force would be required to produce an acceleration of 2ms^-2 in a ball of 4Kg?

1. 10N
2. 6N
3. 8N
4. 4N

Q.

A body of mass $5kg$ is thrown vertically upwards from ground with a velocity of $20m{s}^{-1}$. What will be its momentum just before hitting the ground? Assume upward direction as positive.

1. $100kgm{s}^{-1}$
2. $-100kgm{s}^{-1}$
3. $0kgm{s}^{-1}$
4. $-20kgm{s}^{-1}$

Q.

According to Newtons second law of motion, force is directly proportional to the rate of change of momentum provided

Q.

A body of mass $5kg$ is thrown vertically upwards from ground with a velocity of $20m{s}^{-1}$. What will be its momentum just before hitting the ground? Assume upward direction as positive.

1. $100kgm{s}^{-1}$
2. $0kgm{s}^{-1}$
3. $-20kgm{s}^{-1}$
4. $-100kgm{s}^{-1}$

Q. What is the mass of a block if an acceleration of 2ms^-2 is produced on applying 50N force?

1. 60kg
2. 10kg
3. 30kg
4. 25kg

Q.

When an object is dropped from a height, it accelerates and falls down. The force which accelerates the object is

1. Frictional force

2. Buoyant force

3. Magnetic force

4. Gravitational force

Q. A constant force acting on a body of mass 3.0 kg changes its speed from 2.0 m/s to 3.5m/s in 25 s. The direction of the motion of the body does not changes. What is the magnitude of the force?

1. 0.40N
2. 0.30N
3. 0.10N
4. 0.18N

Q.

Starting from rest, the velocity of a freely falling body, after one second is ___m/s. (Round your answer to the nearest integer)

Q. A force of $20N$ acting on a body of mass $10kg$ is found to double its velocity in $8s$. Find its initial velocity.

1. $32m{s}^{-1}$
2. $16m{s}^{-1}$
3. $8m{s}^{-1}$
4. $4m{s}^{-1}$

Q. If mass and radius of the Earth are $6.0\times {10}^{24}kg$ and $6.4\times {10}^{6}m$ respectively. Calculate the force exerted by the Earth on a body of mass 1 kg, acceleration of the body of mass 1 kg and acceleration of the Earth in order.
Use $G=6.67\times {10}^{-11}N{m}^{2}k{g}^{-2}$

1. $9.8N$
   $9.8m{s}^{-2}$
   $1.63\times {10}^{-24}m{s}^{-2}$
2. $9.8N$
   $9.8m{s}^{-2}$
   $1m{s}^{-2}$
3. $9.8N$
   $9.8m{s}^{-2}$
   $9.8m{s}^{-2}$
4. $9.8N$
   $1.63\times {10}^{-24}m{s}^{-2}$
   $9.8m{s}^{-2}$

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

Q.

While an athlete is running at a constant acceleration of $4.5m{s}^{-2}$, he exerts a force of $300N$. What is the mass of the athlete?

1. $64kg$

2. $65kg$

3. $66.67kg$

4. $69.6kg$

Q. An object moves with an acceleration of 3 ${ms}^{-2}$ when a force of 30 N is applied. The mass of the body is ___ kg.

1. 10
2. 60
3. 30
4. 15

Q. If mass and radius of the Earth are $6.0\times {10}^{24}kg$ and $6.4\times {10}^{6}m$ respectively. Calculate the force exerted by the Earth on a body of mass 1 kg, acceleration of the body of mass 1 kg and acceleration of the Earth in order.
Use $G=6.67\times {10}^{-11}N{m}^{2}k{g}^{-2}$

1. $9.8N$
   $9.8m{s}^{-2}$
   $9.8m{s}^{-2}$
2. $9.8N$
   $9.8m{s}^{-2}$
   $1m{s}^{-2}$
3. $9.8N$
   $9.8m{s}^{-2}$
   $1.63\times {10}^{-24}m{s}^{-2}$
4. $9.8N$
   $1.63\times {10}^{-24}m{s}^{-2}$
   $9.8m{s}^{-2}$

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

Q. An object moves with an acceleration of 3 ${ms}^{-2}$ when a force of 30 N is applied. The mass of the body is ___ kg.

1. 30
2. 10
3. 60
4. 15

Q. A $10\text{kg}$ iron dumbbell is dropped from a height of $80\text{cm}$ onto a stone floor. If the dumbbell comes to rest after hitting the floor, how much momentum (in ${\text{kg m s}}^{-1}$ ) will the floor acquire? Take the acceleration caused in the dumbbell due to gravity, to be $10{\text{m s}}^{-2}$

1. 40