HP 6-2 Work and Power

6-2 Explain: Work and Power

Mr. Custer's Physics​

​Today's

Date​

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Learning Objectives

1. ​Define Work.

2. Identify forces that are doing Work​.

Poll

It is possible to get more Work out of a machine than you put in it.

• Yes

• No

• Sometimes

Poll

Simple Machines make Work easier.

• Yes

• No

• Sometimes

Poll

Which of these situations involves more Work being done?

• Walking up three sets of stairs to get to CSSM.

• Taking the elevator to get up to CSSM.

• The same amount of Work is being done.

Poll

If you push against a School Bus until you are exhausted, but the bus didn't move anywhere, did you do any Work?

• Yes

• No

• Sometimes

A transfer of Energy that involves a Force applied through a distance.

What is Work?

​

No Motion means

No Work​!

When applying a Force, not all components do Work.

Examples of Work being done​

Examples of No Work being done​

Multiple Choice

When the distance an object moves is zero, the work done on the object is also zero.

• True
• False

Multiple Choice

You push against the back of your friends car that is stuck. You push and become very tired, but the car does not move. Did you do Work?

• Yes, work was done.

• No, work wasn't done.

Multiple Choice

In which of these cases is work being done? 

• A student sleeps in class.

• A student pushes a locked door that does not open.

• A student carries his chair into another room.

• A student sits on the carpet.

​

​

How many Newtons of force did you apply in the direction of motion?

Multiple Choice

What would 54 N be an example of?

• work

• distance

• force

• energy

Multiple Choice

What would 14,000 J be an example of?

• work

• time

• force

Multiple Choice

What would 15 m be an example of?

• work

• force

• time

• distance

Multiple Choice

A 5,000 N block is lifted 10 m. How much work was done?

• 50,000 J

• 5,000 J

• 500 J
• 50 J

Multiple Choice

A person weighing 600 N gets on an elevator. The elevator lifts the person 6 meters in 10 seconds.  How much Work was done?

• 100 J 

• 6,000 J

• 3,600 J

• 60 J

Multiple Choice

If 150 Joules of work is needed to move a box 10 meters, what force was used? 

• 1500 N
• 15 N
• 1.5 N
• 150 N

(no, that's not a question)

Watt is the unit of Power​

Multiple Choice

Power is defined as __________.

• force times distance

• force divided by time.

• work divided by time.

• work times time.

• force times time

Multiple Choice

A person weighing 600 N gets on an elevator. The elevator lifts the person 6 m in 10 seconds.  How much power was used?

• 360 W 
• 60 W
• 3600 W
• 600 W

Multiple Choice

An Xbox consumes 15.7 Watts while in standby mode. If you leave it in standby mode for one day (86,400 seconds), how much energy is consumed? (How much Work was done)?

• .000018 J

• 1,356,480 J
• 5,503.18 J

Any Questions before a Five-Question Quiz?

Multiple Select

What two things are required for work to be done? Select both.

• Force is Applied

• Moves a Distance

• Stays at a Constant Speed

• Experiences Friction

• Remains Motionless

Multiple Choice

Consider the system of a block of wood and Earth. Identify the situation in which a force does positive work on an object in the system described.

• A block of wood is held in place against a wall with a large normal force.

• A block of wood is slowing down because of a frictional force.

• A block of wood is sitting on a scale, and its weight is measured to be 25 newtons.

• A block of wood is pushed across a tabletop by a student.

Multiple Choice

A weightlifter lifts two 300 newton weights 1.5 meters off the ground. How much work has she done?

• 600 J

• 450 J

• 900 J

• 1200 J

Multiple Choice

50 J of work is done lifting a 20.0 N book in the air. How high was it lifted?

• 2.5 m

• 3.5 m

• 0.4 m

• 25 m

Multiple Choice

You do 90 Joules of work in 30 seconds. How much power have you generated?

• 30 watts
• 3 watts
• 120 watts
• 270 watts