Question

a horizontal force of 4N acts on a body of mass 40 kg to move it by a distance of 2cm on a table the kinetic energy acquired by the body is​

Answer 1

Answer:

K.E acquired by the body = 0.08 J

Explanation:

We know K.E acquired by a body is equal to the work done on the body.

Since here work done on the body is = Force × displacement = (4 × 0.02) J = 0.08 J

So K.E acquired by the body = 0.08 J.

ALTERNATIVE METHOD ;

Acceleration of the body, a = F / m = 4/40 m/s^2 = 0.1 m/s^2

Displacement of the body, s = 2 cm = 0.02 m

So from relation V^2 = U^2 + 2.a.s we get

V^2 = ( 2×0.1×0.02) = 1/250 m^2/s^2 ( since U = 0)

So K.E acquired by the body = 1/2 × ( m × V^2)

= 1/2 × ( 40 × 1/250) J

= 0.08 J