Question

Assertion (A): A change in the acceleration of an object is directly proportional to the force producing it and inversely proportional to its mass . Reason(R): Lighter mass will travel at a faster speed. (a) Both (A) and (R) are true , but (R) is not the correct explanation of (A) (b) Both (A) and (R) are true and (R) are true and (R) is the correct explanation of (A) (c) (A) is true, but (R) is false. (d) (A) facilitates poor coordination .​

Answer 1

ey Points

Newton’s three laws of physics are the basis for mechanics.

The first law states that a body at rest will stay at rest until a net external force acts upon it and that a body in motion will remain in motion at a constant velocity until acted on by a net external force.

Net external force is the sum of all of the forcing acting on an object.

Just because there are forces acting on an object doesn’t necessarily mean that there is a net external force; forces that are equal in magnitude but acting in opposite directions can cancel one another out.

Friction is the force between an object in motion and the surface on which it moves. Friction is the external force that acts on objects and causes them to slow down when no other external force acts upon them.

Inertia is the tendency of a body in motion to remain in motion. Inertia is dependent on mass, which is why it is harder to change the direction of a heavy body in motion than it is to change the direction of a lighter object in motion.

Key Terms

inertia: The property of a body that resists any change to its uniform motion; equivalent to its mass.

friction: A force that resists the relative motion or tendency to such motion of two bodies in contact.

uniform motion: Motion at a constant velocity (with zero acceleration). Note that an object in motion will not change its velocity unless an unbalanced force acts upon it.

Answer 2

(a) Both (A) and (R) are true , but (R) is not the correct explanation of (A) is correct about mass.

1. The assertion is in accordance with Newton's second law of motion, which states the relationship between acceleration, mass and force.
2. Mathematical form of Newton's second law of motion is F = m*a, where F stands for force, m represents mass and a stands for acceleration.
3. As mass and acceleration are inversely proportional to each other, thus lighter mass will have faster speed.