Question

By what factor do you multiple the kinetic energy of a moving body if you: a) double its mass? b) reverse its direction c) double its speed d) change its direction by 45 degrees

Answer 1

We know, K.E = 0.5 x m x v²

a) so, if mass is doubled than K.E will also get doubled, so we will multiply the K.E by 2

b) when the direction is reversed, keeping the mass and speed same, the K.E will remain same, as K.E is a scalar quantity, and as mass and speed are same so K.E will also remain same.

c) when speed is doubled K.E will increase 4times as it is propotional to square of speed.

d) when the direction is changed by 45 degrees keeping mass and speed same, there will be no effect on the K.E as K.E does not depend upon the direction as it is a scalar quantity.