Question

4.
If momentum of an object is increased by 10% then its kinetic energy will increase by
(1) 20%
(2) 21%
(3) 40%
(4) 19%

Answer 1

Answer:

b)21 percent

Explanation:

There are two case for change of momentum. First by ((increase in mass and keeping the velocity unchanged, the second by keeping the mass unchanged and changing the velocity.

Case1. Velocity unchanged, mass increases by 10%.

Let the original massif the body = m,

New increased mass 1.1 m

Let the velocity be = v

K. E with original mass = 1/2 m v²

K. E with increased mass = 1/2 × 1.1 m v²

Change in K. E= 1/2 m v² (1.1 - 1) = 0.1 of original K. E =10% change in K. E.

Case2: Mass unchanged velocity increases

Original velocity= v

Original K. E= 1/2 m v²

Changed velocity= 1.1 v

New K. E. = 1/2 m (1.1 v)² = 1.21 of original K. E.

% change in K. E= [(1.21 - 1) of original K. E/ original K. E]×100= 21%

Answer 2

Answer:

Am i

Explanation:

option A).................... i guess it