题目

1.Locomotive exert on a 12320-kg boxcar to make it accelerate forward at 0.57 m/s2.How long will it take the boxcar to reach its cruising speed of 82 km/h (51.0 mph or 22.8 m/s)?
2.The builders of the pyramids used a long ramp to lift 22000-kg (22-ton) blocks.How much work was done in raising one of the blocks to a height of 53
3.If your car accelerates from rest at a steady rate of 4 m/s2,how soon will it reach 88 km/h (54.7 mph or 24.4 m/s)?
4.On Mars,the acceleration due to gravity is 3.71 m/s2.How far would a rock fall in 5 s if you dropped it on Mars?
5.A basketball player can leap upward 0.44 m.What is his initial velocity at the start of the leap?
6.A sprinter can reach a speed of 9.4 m/s in 0.95 s.If the sprinter’s acceleration is constant during that time,what is the sprinter’s acceleration?
7.How much does a 84-kg person weigh on earth?
8.As water descends from the top of a tall hydroelectric dam,its gravitational potential energy is converted to

提问时间：2020-11-23

答案

1.Locomotive exert on a 12320-kg boxcar to make it accelerate forward at 0.57 m/s2.How long will it take the boxcar to reach its cruising speed of 82 km/h (51.0 mph or 22.8 m/s)?已知：V0=0,m=12320kg,a...