Question

A car of mass 100 kg starts moving on a horizontal road from a point o take the horizontal plane containing o as reference level for gravitational potential energy g=10m/s^2 the car reaches point A with speed 72km/hr calculate the mechanical energy

Answer 1

$$E=0.5mv^2\\E=0.5(100)\frac{72^2}{3.6^2}=20000\ J$$