Question

An object with a mass of 3.50 kg moves in a straight line on a frictionless horizontal surface with a speed of 2.0 m/s. Find the kinetic energy and the net work done on the object to make it reach this speed if it started from rest.

Answer 1

Given:

$v_f=2.0\rm\: m/s$

$v_i=0\rm\: m/s$

$m=3.50\rm\: kg$

The final kinetic energy

$$E_{kf}=\frac{mv_f^2}{2}=\frac{3.50*2.0^2}{2}=7.0\:\rm J$$

The work done

$$W=E_{kf}-E_{ki}=7.0-0=7.0\:\rm J$$