Question

Calculate the kinetic energy of a car of mass 750kg moving with a velocity of 72km/hr find the kinetic energy if the velocity of car becomes 3times

Answer 1

mass of car=750kg
velocity=72 km/hr ×5/18=20m/s
kinetic energy=1/2×m×v×v
kinetic energy=1/2×750×20×20
kinetic energy=750×20×10
kinetic energy=150000J


if velocity become three times then
v=72×3=216km/hr×5/18=60 m/s
then
kinetic energy=1/2×m×v×v
kinetic energy=1/2×750×60×60
kinetic energy=750×60×30
kinetic energy=1350000J