Exam 5: Energy

A pile driver drives a post into the ground.The mass of the pile driver is 2,700 kg and it is dropped through a height of 8.0 m on each stroke.If the resisting force of the ground is 3.0 × 10⁶ N,how far is the post driven in on each stroke?

0.8A satellite is held in orbit by a 1,000-N gravitational force.Each time the satellite completes an orbit of circumference 80,000 km,the work done on it by gravity is:

A block is projected with speed v across a horizontal surface and slides to a stop due to friction.The same block is then projected with the same speed v up an incline where is slides to a stop due to friction.In which case did the total mechanical energy of the block decrease the least?

A Hooke's law spring is compressed 12.0 cm from equilibrium and the potential energy stored is 72.0 J.What is the spring constant in this case?

The work done by static friction can be:

A 1,200-kg automobile moving at 29 m/s has the brakes applied with a deceleration of 3.0 m/s².How far does the car travel before it stops?

Old Faithful geyser in Yellowstone Park shoots water hourly to a height of 30 m.With what velocity does the water leave the ground?

A golf ball hits a wall and bounces back at 1/3 the original speed.What part of the original kinetic energy of the ball did it lose in the collision?

A 100-W light bulb is left on for 10.0 hours.Over this period of time,how much energy was used by the bulb?

Samantha pushes a 50-N crate up a ramp 25 m in length and inclined at 10° with the horizontal.What potential energy change does the crate experience?

Three different mass projectiles are launched from the top of a building each at different angles of elevation.Each particle has the same initial kinetic energy.Which particle has the greatest kinetic energy just as it impacts with the ground?

A worker pushes a sled with a force of 37 N over a level distance of 5.0 m.If a frictional force of 21 N acts on the wheelbarrow in a direction opposite to that of the worker,what net work is done on the wheelbarrow?

A girl and her bicycle have a total mass of 42 kg.At the top of the hill her speed is 5.0 m/s.The hill is 10 m high and 100 m long.If the force of friction as she rides down the hill is 25 N,what is her speed at the bottom?

A parachutist of mass 52.0 kg jumps out of an airplane at a height of 1 080 m.The parachute deploys,and she lands on the ground with a speed of 6.0 m /s.How much energy was lost to air friction during this jump?

A 1.00-kg ball has zero potential and kinetic energy.Maria drops the ball into a 10.00-m-deep well.After the ball comes to a stop in the mud,the sum of its potential and kinetic energy is:

I drop a 65-g golf ball from 3.0 m high.It rebounds to 1.0 m.How much energy is lost?

Which of the following is that form of energy associated with an object's motion?

The unit of work,joule,is dimensionally the same as:

Preston pushes a wheelbarrow weighing 490 N to the top of a 45.0-m ramp,inclined at 20.0° with the horizontal,and leaves it.Tamara accidentally bumps the wheelbarrow.It slides back down the ramp,during which an 80.0-N frictional force acts on it over the 45.0 m.What is the wheelbarrow's kinetic energy at the bottom at of the ramp? (g = 9.8 m/s²)

By how much is the energy stored in a Hooke's law spring increased when its stretch is increased from 6.00 cm to 15.00 cm?