Question

a 1000-kg car is moving at 15 km/h. if a 2000-kg truck has 23 times the kinetic energy of the car, how fast is the truck moving? 51 km/h 72 km/h 61 km/h 41 km/h

Answer 1

51 km/hr

Step-by-step explanation:

car: KE = 1/2mv² = 1/2(1000 kg)(15 km/hr)² = 112500

truck: KE = 23(112500) = 2587500

KE = 1/2mv² → v² = 2(KE)/m → v = √2(KE)/m

v = √2(2587500)/(2000 kg) = 50.9 ≈ 51 km/hr