Question

Consider the following three sentences: (a) A spaceship glides through the solar system with a constant velocity. (b) As it gets close to an asteroid, the asteroid attracts the spaceship and the spaceship the asteroid. Both experience the same force. (c) The spaceship starts accelerating with an acceleration that is proportional to the gravitational force and inversely proportional to the its own mass. “The acceleration is proportional to the force” means the acceleration scales with the force: the stronger the force, the larger the acceleration. “The acceleration is inversely proportional to its mass” means the acceleration scales with 1 / (spaceship mass): the more massive the spaceship, the smaller is its acceleration – for a given fixed strength of the force

. Explain each of Newton’s three laws in your own words, and explain to which of the above sentences (a), (b) or (c) it related most closely.

Answer 1

First law :- A body is said to be in motion until and unless it gets stopped by an object or due to friction. It will keep on going i.e.motion

Second law: The force is directly proportional to the product of mass of body and the acceleration of body. The rate of change of momentum is equal to force exerted on body.

Third Law:- Every action has equal and opposite reaction. Every force exerted on the body will exert a force on hand that will be equal and opposite.

(a) relates to first law of motion as the spaceship glides into space with constant velocity.

(b) relates to third law of motion as both asteroid and spaceship exerted forces on each other that are equal and opposite.

(c) relates to second law of motion as acceleration(a) is proportional to force(F) and inverserly to mass(m) i.e. a = F/m Or F = ma