A roller coaster starts from rest at its highest point and then descends down a frictionless track. Its speed is 30 m/s when it reaches ground level. What was its speed when its height was half that of its starting point?
What is 21 m/s
A 2 kg book is lying on a .75 m table. You pick it up and place it on a bookshelf 2.3 m above the floor. How much work did your hand do on the book?
What is 31 J
At what speed does a 1000 kg compact car have the same kinetic energy as a 20,000 kg truck going 25 km/h?
What is 112 kg/h
The lowest point of Death value is 85 m below sea level. The summit of nearby Mt. Whitney has an elevation of 4420m, What is the change in gravitational potential energy of an energetic 65 kg hiker who makes it from the floor of Death Valley to the top of Mt. Whitney?
What is 2,928,250 J
A weightlifter lifts a 200 N barbell from the floor to a height of 2 m. How much work is done?
What is 400 J