Work and Energy

In which of the following situations do your arms do work on books?

• holding a heavy stack of books while standing

• dropping a stack of books onto a table

• picking up a pile of books from the floor

• carrying a heavy stack of books

How much work is done lifting a 9.10-kg box straight up onto a shelf that is 1.80 m high? Find Force by F = Mass x Acceleration

• 5 J

• 160 J

• 16 J

• 50 J

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-4

What are three ways that simple machines can make work easier?

• changing the direction of force, increasing speed, increasing force

  with

• changing the direction of speed–increasing direction– increasing force–

• changing the force of speed–decreasing direction– increasing force–

• scissors, tractors and a car jack are simple machines that make work easier.

Using the scientific definition, which statement is always true of work?

• It is difficult.

• It is done with a machine.

• It involves levers.

• It involves a transfer of energy.

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Name and describe at least two examples of how different forms of energy can be stored.

• a spring can store energy by chemically bonding the tension. A battery can store energy by mechanically having it in the system.

• Chemical potential energy is stored due to fire burning Gravitational potential energy is stored due an object at the bottom of the hill and storing it.

• Chemical potential energy is stored due to the molecular bonds of food and fuels. Gravitational potential energy is stored due to the gravitational attraction between Earth and the Sun. Elastic potential energy is stored by stretching or compressing a spring.

• Gasoline can store energy by thermal energy. The sun can store energy by also using thermal energy

Tags

NGSS.HS-PS1-4

The kinetic energy from an object’s motion always changes when which factor changes?

• the object's speed

• the object's volume

• the object's chemical potential energy

• the object's direction of motion

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5

According to the graph, what is the kinetic energy at 2 s?

• 200 J

• 10 J

• 21 J

• 15 J

Tags

NGSS.MS-PS3-1

At which position(s) does the pendulum have maximum gravitational potential energy

• Position 1 and 5

• Position 1 and 3

• Position 5

• Position 1

Tags

NGSS.MS-PS3-2

At which position(s) does the pendulum have maximum kinetic energy

• Position 3

• Position 1

• Position 5

• Position 2 and 4

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5

The kinetic energy of the golf club would be greatest at

• point A

• point B

• point C

• point D

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5