AP Physics Work and Energy

While moving a level lawn, Bill applies a force of 20 N directed at an angle of 60 degrees below the horizontal. How much work does he do pushing the mower a distance of 10 m?

• 100 J

• 174 J

• 200 J

• 0 J

• -200 J

A spring with a spring constant of 100 N/m is compressed a distance of 0.1 m horizontally. When the spring is released, it pushes a 0.25 kg mass that was initially at rest against the spring. What is the maximum speed attained by the mass?

• 0 m/s

• 1 m/s

• 20 m/s

• 0.1 m/s

• 2 m/s

Tags

NGSS.HS-PS2-1

NGSS.HS-PS3-1

A 4,000 kg elevator rises from the basement to the top of a 100 m tall building. Which of the following is closest to the net work done on the elevator as it rises through the middle 20 m of its trip at constant velocity? Use g = 10m/s^2

• 800,000 J

• -800,000 J

• 80,000 J

• -80,000 J

• 0 J

Tags

NGSS.MS-PS2-4

NGSS.MS-PS3-2

A 4,000 kg elevator rises to the top of a tall building. What is closest to the work done on the elevator by Earth's gravity as it rises a height of 20 m at constant velocity near the middle part of its ascent? Use g =10m/s^2

• 800,000 J

• -800,000 J

• 80,000 J

• -80,000 J

• 0 J

Tags

NGSS.HS-PS2-4

NGSS.HS-PS3-1

A roller coaster at a theme park is traveling at a speed of 20 m/s just before it starts up a hill. If the roller coaster barely makes it over the hill, which of the following is closest to the maximum possible height of the hill? Use g = 10 m/s^2 and neglect friction

• 1 m

• 400 m

• 50 m

• 20 m

• To answer this question, one must know the mass of the roller coaster

Tags

NGSS.HS-PS3-1

A block of mass 9kg slides a distance of 5m down a 30 degrees incline as shown. How much work is done on the block by gravity?

• 450 J

• 225 J

• 390 J

• 90 J

• 0 J

How much energy does a 100 W light bulb consume in an hour?

• 100 J

• 100 W

• 360,000 J

• 360,000 W

• 60 J

A ball of mass m is thrown from a height h with an initial speed v0 at an initial angle of theta. Which of the following expressions gives the speed, v, at which the ball will strike the ground?

• v=(2gh)^1/2

• v=(2gh +v0^2 sin(theta))^1/2

• v=(2mgh +v0^2 sin(theta))^1/2

• v=(2gh + v0^2)^1/2

• v=(2gh +v0^2 tan(theta))^1/2

Tags

NGSS.HS-PS2-1

NGSS.HS-PS3-1

NGSS.HS-PS3-2

A person with a mass of 80 kg runs up a flight of stairs in 4 seconds. If the elevation gain is 4 m, what is the power the person expends against gravity?

• 80 W

• 320 W

• 800 W

• 3,200 W

• 12,800 W

There is a potential energy associated with gravitational and spring forces. Is there also a potential energy associated with frictional forces?

• No, because gravitational and spring forces are the only forces that have an associated potential energy

• Yes, because gravitational, spring, and frictional forces are all conservative

• No, because frictional forces are conservative, while gravitational and spring forces are not

• Yes, because all forces have an associated potential energy

• No, because gravitational and spring forces are conservative, while frictional forces are not