Question

A cabbie is trying to stop when he notices a fare is whistling them over. The
car has 18750 J of energy. If the cab is 2100. kg, how fast was it moving?

Answer 1

• K.E=18750J
• Mass=m=2100kg
• Velocity=v

$\boxed{\sf K.E=\dfrac{1}{2}mv^2}$

$\\ \sf\longmapsto 18750=\dfrac{1}{2}2100v^2$

$\\ \sf\longmapsto 18750=1050v^2$

$\\ \sf\longmapsto v^2=\dfrac{18750}{1050}$

$\\ \sf\longmapsto v^2=17.85m^2$

$\\ \sf\longmapsto v=\sqrt{17.85}$

$\\ \sf\longmapsto v=4.1m/s$