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

问题描述:

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 electric energy.How much gravitational potential energy is released when 900 kg of water descends 230 m to the generators?
9.You’re using a wedge to split a log.You are hitting the wedge with a large hammer to drive it into the log.It takes a force of 3100 N to push the wedge into the wood.If the wedge moves 0.2 m into the log,how much work have you done on the wedge?
10.You’re sanding a table.You must exert a force of 32 N on the sandpaper to keep it moving steadily across the table’s surface.You slide the paper back and forth for 21 minutes,during which time you move it 1000 m.How much work have you done?

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...