Unit 5 Review: Energy

A 3-N force is exerted on a box, moving it 20 m in the same direction.

According to the above diagram, what is the magnitude of work done on the box?

• 60 J

• 0.2 J

• 7 J

• 20 J

Tags

NGSS.MS-PS2-2

NGSS.MS-PS3-5

Conveyor belts are often used to move packages around warehouses. The conveyor shown below moves packages at a steady 4.0 m/s. A 50 N employee decides to catch a ride by sitting on a 2050 N box for a 50 m trip as shown below.

What is the work done by the employee on the box shown above?

• 0 J

• 105,000 J

• 2500 J

• 102500 J

Answer explanation

Moving at a constant velocity, therefore, no work is done.

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5

What is the total work done by gravity on an object that is lifted up and then lowered down back to its starting point?

Mathematical Equivalence

ON

Answer explanation

The total work done by gravity would be 0.

Since the work would be negative on the way up and positive on the way down, adding to 0.

Tags

NGSS.MS-PS3-4

A 150 kg gymnast comes to a stop after tumbling. Her feet do 2,000 J of work to stop her. Which of the following was the girl's velocity when she began to stop?

• 10 m/s

• 5 m/s

• 300000 m/s

• 27 m/s

Tags

NGSS.MS-PS2-2

NGSS.MS-PS3-1

NGSS.MS-PS3-4

NGSS.MS-PS3-5

A 22.0 N net force is applied to an object as it moves a distance of 7.00 m. Use the Work–Kinetic Energy Theorem to determine the object's change in kinetic energy. Enter your answer in Joules. Record your answer. Be sure to use the correct place value.

Mathematical Equivalence

ON

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Calculate the potential energy of a 9.00 kg bowling ball suspended 2.00 m above the surface of the Earth.

• 18.00 J

• 176 J

• 794 J

• 4.50 J

Tags

NGSS.MS-PS2-4

NGSS.MS-PS3-2

A student examines the relationship between gravitational potential energy and position of a ball above the ground as shown in the graph below.

What does the slope of the above graph represent?

• Acceleration due to gravity

• Mass

• Potential Energt

• Weight

Tags

NGSS.MS-PS3-2

A tennis ball launcher works by using a spring to propel the ball forward as shown below:

One model of tennis ball launcher has advertised that it is capable of imparting 5500 J of kinetic energy to a 1.5 kg ball initially at rest. A student carefully measures the compression of the spring to be 0.50 m.

What is the value of the velocity for the tennis ball according to the data provided? Choose the correct equation and answer below:

• 86 J

• 245 J

• 4130 J

• 128 J

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5

Which of the following is the best example of kinetic energy being transformed into potential energy?

• Coasting down a hill on a bicycle

• A skateboarder on a skate board going up a ramp

• Stretching a rubberband

• Sitting at the top of a Roller Coaster

Answer explanation

KE-->PE

The object will slow down.

-The bicycle: PE-->KE

-The skateboarder: KE-->PE

-Rubber band: PE

-Roller Coaster: PE

Tags

NGSS.MS-PS3-5

Which of the following does contribute ONLY to the kinetic energy of an object?

• Height of the object above the Earth's surface

• Gravitational constant, or g, of the Earth

• Velocity of the object

• Mass of the object

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5