Apparent Weight

Q.

Two stones of different masses are thrown vertically upward with the same initial velocity. Which one will rise to a greater height?

Q. Weightlessness experienced while orbiting the Earth in International Space Station, is the result of

1. zero gravity
2. free fall towards Earth
3. inertia

Q.

Why is it difficult to walk on Sand ?
(a) Because Sand is soft and does not oppose motion
(b) Because Sand is soft and opposes motion
(c) Because Sand does not yield high Reaction forces required for Walking
(d) Because Sand yields Reaction forces required for Walking.

Q. A force of 72 dyne is inclined to the horizontal at angle of 60* find a in a mass of 9g which moves in the effect of this force in a horizontal direction

Q. Reason of weightlessness of any body in a satellite is zero .

1. gravity
2. mass
3. reaction force

Q.

When a fast-moving vehicle is suddenly stopped by applying brakes, the force that causes deceleration is exerted by the brake.

1. Due to opposing force of friction

2. Because action and reaction pair are never equal

Q.

Name the physical quantity associated with kg-m/s.

Q.

Choose the correct option regarding the strength of Gravitational force.

1. Gravitational force is approximately 10^-38 times the strength of the nuclear force

2. Gravitational force is the weakest amongst all the fundamental forces of nature.

3. Gravitational force has negligible influence when considered on an atomic scale.

4. All of these

Q.

A boy $P$ has a mass $20kg$ and its moving with a velocity of $5m{s}^{-1}$.Another boy $Q$ has a mass of $5kg$and is moving with a velocity of $20m{s}^{-1}$. Calculate the ratio of the momentum of $P$ and $Q$.

1. 2:1

2. 1:1

3. 1:2

4. 3:2

Q.

Define the momentum of an object. Write SI unit of momentum.

Q. nta mass of 2 kg is put on a flat pan attached to the vertical spring fixed on the ground as shown in the figure. the mass of the spring and pan is negligible.n ntwhen pressed slightly and released the mass executes an shm. the spring constant is 200 n/m. what should be the minimum amplitude of the motion son ntthat the mass gets detached from the pann

Q.

Why do astronauts feel weightless in a satellite?

1. zero gravity

2. zero reaction force due to the satelllite surface

3. centre of mass

4. can’t be said

Q. An object of mass 1 kg travelling in a straight line with a velocity of $10m{s}^{-1}$ collides with, and sticks to, a stationary wooden block of mass 5 kg. Then they both move off together in the same straight line. Calculate the total momentum just before the impact and just after the impact. Also, calculate the velocity of the combined object.

Q.

A projectile weighing 200 kg is fired from a gun with a velocity of 500 m/s. If the velocity of recoil of the gun is 12.5 m/s. Calculate the mass of the gun.

Q.

Write down the units and dimensional formulae of following physical quantities:
$Momentum=mass\times velocity$

Q.

An astronaut finishes some work on the outside of his satellite, which is in circular orbit around the earth. By mistake, his wrench gets released from his hand, the wrench will continue to move in same orbit.

1. True
2. False

Q.

Reason of weightlessness in a satellite is

1. the centre of mass

2. can’t be said

3. zero reaction force due to the satellite surface

4. zero gravity

Q.

Name the physical quantity which is the product of mass and velocity.

Q. Match the following, according to the state of lift with the apparent weight of any person in lift.

1. $R>W$
2. $R=W$
3. $R<W$
4. $R=0$

Q.

On the basis of newton’s second law of motion proves that the rate of change of momentum of an object is equal to the force applied to it.

Q. Weightlessness is a condition in which effective of the body becomes .

1. mass
2. weight
3. $zero$
4. $9.8N$

Q.

A parrot is sitting on the floor of a closed glass cage which is in a boys hand. If the parrot starts flying with a constant speed, the boy will feel the weight of the cage as

1. unchanged

2. reduced

3. increased

4. nothing can be said

Q.

A body P has a mass of 2 m and velocity of 5 v. Another body Q has a mass of 8 m and velocity of 1.25 v. The ratio of momentum of P and Q is :

1. 2:1

2. 1:1

3. 1:2

4. 3:2

Q.

Define momentum and write down its unit.

Q. Two objects of different masses released from rest at the same time falling freely near the surface of moon would ___.

1. have the same velocities at any instant
2. have different accelerations
3. experience forces of same magnitude
4. undergo a change in their mass

Q.

Explain momentum with an example.

Q. The reaction force exerted by the table on $100g$ book which is kept stationary on table is .($g=10m{s}^{-2}$)

1. $10N$
2. $0.1N$
3. $1N$

Q. A body of mass $m$ is in vertical motion under the influence of gravity then

1. work will be negative and kinetic energy increases during fall.
2. kinetic energy decreases when body is projected up and work will be negative.
3. kinetic energy increases when body is projected up and work will be positive.
4. work will be positive and kinetic energy decreases during fall.

Q. Statement A: When a person is on the floor of a lift which is at rest, the reaction force on him is equal to his weight.
Statement B: When the lift is moving with uniform velocity, then the apparent weight of the man is zero.

1. A is wrong and B is correct.
2. A & B are correct.
3. A is correct and B is wrong.
4. A & B are wrong.

Q. A man in the lift weighs more, when the lift .

1. begins to go up
2. begins to go down
3. is in free fall