Question

What is the new velocity of a 1140 kg car that was traveling at 13.6 m/s and slams on the brakes losing 5000J of energy?

Answer 1

Answer:

13.3 m/s

Explanation:

KE = 1/2 m • v^2

KE = 1/2 • 1140 kg • (13.6m/s )^2

KE = 105427.2 J

KE after brakes are slammed = 105427.2 J - 5000 J

KE after brakes are slammed = 100427.2 J

100427.2 J = 1/2 • 1140 • v^2

v = (100427.2 J • 2 / 1140 kg)^1/2

v = 13.3 m/s after adjusting for significant figs