NEET Physics: Momentum questions with solutions

Q1. A body is projected vertically upwards. Its momentum is gradually decreasing. In this

1. it is a violation of law of conservation of linear momentum
2. momentum of the body alone gets conserved
3. momentum of the body, earth and air molecules together remains constant
4. violates law of conservation of energy.

Answer: momentum of the body, earth and air molecules together remains constant

As the body rises, gravity and air resistance reduce its momentum, but those are internal interactions if you consider the body, Earth, and air together. For the complete isolated system, total linear momentum remains constant.

Q2. Newton used the phrase 'quantity of motion' for

1. Momentum
2. Force
3. Acceleration due to gravity
4. None of these

Answer: Momentum

Newton’s “quantity of motion” refers to the product of mass and velocity, which is momentum. It measures how much motion an object has and how difficult it is to bring to rest.