Newton's Third Law

Q.

Since action and reaction forces are always equal and opposite, how can motion then take place?

Q.

Derive the law of conservation of momentum from Newtons third law of motion.

Q. Newton's third law of motion leads to the law of conservation of .

1. energy
2. linear momentum
3. velocity

Q. The action and reaction forces act on at the .

1. on same body
2. on different bodies
3. at different times
4. at same time

Q. Which of the following is true about action-reaction forces in Newton’s third law of motion?

1. They must act on different objects in the same direction.
2. They must act on different objects in opposite directions.
3. They must act on the same object in the same direction.
4. They must act on the same object in opposite directions.

Q.

State Newtons first law of motion. Explain it by giving an example.

Q. Conservation of momentum is a direct consequence of which law?

1. Newton's first law of motion
2. Newton's second law of motion
3. Newton's third law of motion
4. Newton's law of gravitation

Q.

Explain which of Newtons laws of motion are appli­cable in the following cases.

1. A person swimming in water.
2. A person gets hurt when jumping on the hard cement surface.
3. A mango falls from the tree when the branch of the tree is suddenly shaken.
4. The recoil of the gun when the bullet is fired from it.
5. To compare accelerations produced in spheres of mass $m$and $2m$, when equal force is applied to them.

Q.

Force can be defined as

Q.

newtons third law

Q. Do action and reaction forces act simultaneously? Explain.

Q. Derive the equation of motion

Q. Propulsion of rockets is based on the .

1. conservation of energy
2. newton's third law
3. archimedes' principle

Q.

State the first law of Newton.

Q. A pair of action and reaction forces always have ________ magnitude and _________ direction.

Q.

Which law of newton defines force?

Q. Newton's laws of motion are applicable to frame of reference.

1. inertial
2. non-inertial
3. uniformly accelerated

Q. A body is exerting a force of 10 N on a table. The table will exert a force of on the body.

1. $8\text{N}$
2. $10\text{N}$
3. $12\text{N}$

Q.

Electricity can be used to replace the fuel and power a rocket (using today's mechanism) just like an electric car.

1. True, as Electricity is also a form of energy.

2. False, as Electricity is not a source of energy.

3. False, as the rocket needs to throw out fuel in the opposite direction to move.

4. True, as the mechanism for car and rocket is similar.

Q.

Discuss the law of conservation of momentum.

Q. Which of the following does not affect the escape velocity of a satellite?

1. Mass of the Earth
2. Radius of the Earth
3. Mass of the satellite
4. All of the above.

Q. If an object is rotating freely in space on its axis and suddenly its axis tilt changes then what will be the effect on its angular velocity or speed? Explain.

Q. Question 17
Water sprinkler used for grass lawns begins to rotate as soon as the water is supplied. Explain the principle on which it works

Q. When the fuel in the rocket burns, the rocket moves vertically upward due to :

1. the exhaust gases escape through the nozzle opposite to the earth and pushes downwards
2. the exhaust gases escape through the nozzle opposite to the earth and pushes upwards
3. the exhaust gases escape through the nozzle towards the earth and pushes downwards
4. the exhaust gases escape through the nozzle towards the earth and pushes upwards

Q.

A man is at rest in the middle of a frozen pond. He can get himself to the shore by the implication of :

1. Law of conservation of momentum

2. Newton's third law of motion

3. Newton's first law of motion

4. Law of gravitation

Q. A man is standing at an edge of a boat. He starts moving towards the centre of the boat. As no external force is acting on the system of boat and man, (neglect friction due to water) the boat will move in opposite direction.

1. True
2. False

Q.

A boy hits the football with a large force, the action force acts on the football and same magnitude reaction force acts on the boy. What can be inferred from the statement?

1. Action and reaction force does not cancel each other.

2. Action force and reaction force are equal to each other.

3. Action and reaction forces acts on two different bodies.

4. All of the above

Q.

A body is kept on a table. The object is pushed downwards with a force equal to its weight. But the table exerts an equal and opposite force on the object, hence keeping it at rest.

1. False

2. True

Q.

If $F_1$ is the magnitude of the force exerted on the Sun by Earth and $F_2$ is the magnitude of the force exerted on Earth by the Sun, then :

1. $F_1=F_2$

2. $F_1>F_2$

3. $F_1<F_2$

4. $F_1$ and $F_2$ cannot be compared

Q. Ravi throws a heavy stone out of his small boat. As results boat moves in opposite direction. Why