Question
1.A 75 kg passenger in a van is wearing a seat belt whent he van moving at 15m/s, collides with a conrete wall. The front end of the van collapses 0.50 m as it comes to rest.
a) what was the paseenger's kinetic energy before the crash
b) What average force did the seat belt exert on the passengfer during the crash?
2. A 1400 kg car is accelerating up a hill. The hill is 150m long and the total rise of the hill is 6.0m. The car accelerates from a speed of 7.0m/s at the bottom to 15m/s at the top. If the average retarding force of friction is 700 N find the change in potential energy of the car, and the change in kinetic energy of the car.
a) what was the paseenger's kinetic energy before the crash
b) What average force did the seat belt exert on the passengfer during the crash?
2. A 1400 kg car is accelerating up a hill. The hill is 150m long and the total rise of the hill is 6.0m. The car accelerates from a speed of 7.0m/s at the bottom to 15m/s at the top. If the average retarding force of friction is 700 N find the change in potential energy of the car, and the change in kinetic energy of the car.
Answers
bobpursley
KE=1/2 m v^2
force*distance=workaborbed=KEinitial
2. change in PE= 1400*g*6m
change in PE=finailKE-initialKE
= 1/2 m (15^2-7^2)
force*distance=workaborbed=KEinitial
2. change in PE= 1400*g*6m
change in PE=finailKE-initialKE
= 1/2 m (15^2-7^2)