Work and Energy — Question 17

Given,

Mass (m) = 1500 kg

Initial velocity (v) = 60 kmh^-1

Final velocity = 0

Converting kmh^-1 to ms^-1 : multiply by $\dfrac{5}{18}$

60 x $\dfrac{5}{18}$ = $\dfrac{50}{3}$ ms^-1

Work required to stop the moving car = Kinetic energy of car (K.E.)

K.E. = $\dfrac{1}{2}$mv²

= $\dfrac{1}{2}$ x 1500 x $(\dfrac{50}{3})$²

= $\dfrac{1}{2}$ x 1500 x $\dfrac{2500}{9}$

= 208333.3 J

Hence, work done = 208333.3 J.