Power and Work

How much work is done when a 45 N force moves a block 20m?

• 900 J

• 2.25 J

• 900 m

• 2.25 W

Tags

NGSS.HS-PS3-1

What is the formula for work?

• Force = work x distance

• Distance = force x work

• Work = force x distance

• Work = force x mass

If two rocks are launched through the air at the same speed, but one has twice as much mass as the other, how do their kinetic energies compare?

• The kinetic energy of the two rocks is the same because they have the same speed

• The rock with the greater mass will only move a small distance and then fall straight to the ground

• The two rock could not have the same speed if they have different masses

• The rock with the greater mass has more kinetic energy than the rock with less mass even though they are traveling at the same speeds because both mass and speed affect kinetic energy.

Tags

NGSS.HS-PS3-2

The rate at which work is done.

• Joules

• Power

• Watts

• Newtons

How much power is used if a force of 35 Newtons is used to push a box a distance of 10 meters in five seconds? (Hint: Solve for work first. This is a 2-step problem.)

• 70 W

• 3.5 W

• 7 W

• 350 J

Tags

NGSS.HS-PS2-1

A set of pulleys is used to lift a piano weighing 1,000 newtons.  The piano lifted 3 meters in 60 seconds  How much power is used?

• 16.67 watts

• 50 watts

Tags

NGSS.MS-PS3-4

In order to do work on an object, the force you exert must be...

• The maximum amount of force you are able to exert.

• In the same direction as the object's motion.

• In a direction opposite to Earth's gravitational force.

• quick and deliberate.

How do we calculate work?

• W = F * d

• w = f / d

Which is the correct unit for work?

• Joules

• Newton

• meter

• Watts

How do you calculate power?

• P = W/t

• P = E/t

• P = w * t

• P = bbq/chicken