Unit 6 Energy

When the speed of an object doubles, its kinetic energy...

• is halved

• quadruples

• doubles

• is squared

Which of the objects below has the most kinetic energy?

• m=8kg, v=20m/s

• m=14kg, v=15m/s

• m=12kg, v=12m/s

• m=100kg, v=3m/s

A 50kg firefighter is working on a ladder 10m above the ground. What will be the firefighter's potential energy decrease by when the firefighter descends to a height of 5m above ground?

• 5J

• 500J

• 250J

• 2500J

An object is pulled forward by a 100-N force and backward by a 60-N force along a horizontal frictionless surface. How much net work is done on the object after it travels 4-m?

• 640J

• 80J

• 160J

• 40J

Tags

NGSS.HS-PS2-1

Victor lifts a hammer he found and just happens to be able to pick up that it has a mass of 19.2 kg, 2 meters high. How much work did he do?

• 384 J

• 0 J

• 38.4 J

• 192 J

A snow monster drags his injured prey across the snow. Assume friction is zero. If the prey has a mass of 80 kg. If the monster applies a constant force of 340 N at an angle of 20 degrees to drag the prey 48 m. How much work did the monster do?

• 16,320 J

• 5,582 J

• 15,336 J

• 38,400 J

Tags

NGSS.HS-PS3-1

Which graph shows the greatest amount of work:

• 1

• 2

• 3

• 4

The chart represents the work output and the time to do the work for four machines. For which machine is the power output least?

• I

• II

• III

• IV

A girl carries a heavy suitcase quickly up a flight of stairs. A boy of the same weight carries the same suitcase slowly up the flight of stairs. Which statement is true?

• The girl did less work and had less power than the boy.

• The girl did more work and had more power than the boy.

• The girl had less power than the boy.

• The girl had more power than the boy.

Tags

NGSS.HS-PS3-2

A child pulls a toy car along a smooth, frictionless floor. The forces in newtons (N) and distances in meters (m) are shown in the graph below. Based on the information in the graph, which of the following represents the correct amount of work in joules (J) to pull the car 8 m?

• 3 J

• 32 J

• 16 J

• 90 J

Tags

NGSS.MS-PS2-2