Work, Power, and Simple Machines

Is holding a book out in front of you and your arms getting tired considered work in a scientific context?

• Yes, because you are using energy

• No, because there is no displacement

• Yes, because it requires effort

• No, because it is not a form of exercise

What is work in the context of physics?

• Any kind of physical or mental activity.

• Using a force to move an object a distance (in the same direction).

• The energy transferred to an object when it is moved by a force.

• The amount of time spent on a task.

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

What is the formula for calculating work?

• Work = Distance / Force

• Work = Force + Distance

• Work = Force x Distance

• Work = Force - Distance

For work to be done, in which direction must the force act?

• Opposite to the direction of the movement

• Perpendicular to the direction of the movement

• In the direction of the movement

• Force direction is irrelevant

When is NO work done according to the concept of physics?

• When an object is moved over a distance by applying force

• When an object is held in place while applying force but no distance is covered

• When an object is moved without applying any force

• When an object is accelerated over a distance

Is work being done when someone is mowing the lawn?

• Yes

• No

• Cannot be determined

• Only if the lawn mower is electric

Is work being done when someone is pushing against a locked door?

• Yes

• No

• Only if the door eventually opens

• Only if the person is pushing very hard

What does power refer to in a scientific context?

• The force applied on an object

• The capacity to perform work

• The rate at which work is done

• The energy transferred over distance

Which formula represents power?

• P = Force × Distance

• P = Work × Time

• P = Work / Time

• P = Distance / Time

What is the unit of power named after James Watt?

• Newton

• Joule

• Watt

• Pascal