Question

A vehicle of mass 1,500 kg is traveling at a speed of 50 km/hr. What is the kinetic energy stored in its mass? Calculate the energy that can be recovered by slowing the vehicle to a speed of 10 km/hr.

Answer 1

Answer:

Explanation:

Given

mass of vehicle $m=1500\ kg$

Speed of vehicle $u=50\ km/hr\approx 13.89\ m/s$

Kinetic Energy Possessed by mass

$K_i=\frac{1}{2}mu^2$

$K_i=\frac{1}{2}\times 1500\times (13.89)^2$

$K_i=144.69\ kJ$

when vehicle is slowed down to speed of $v=10\ km/hr\approx 2.78\ m/s$

Kinetic Energy at this speed

$K_f=\frac{1}{2}mv^2$

$K_f=\frac{1}{2}\times 1500\times (2.78)^2$

$K_f=5.78\ kJ$

Energy Recovered $=K_i-K_f$

Energy Recovered$=144.69-5.78=138.9\ kJ$