Energy conservation calculation

What does the first law of Thermodynamic mean?

• Energy can't be destroyed

• Energy can't be created

• Etotal stays the same

• E_{total i}=E_{total f}

A 60.0-kilogram runner has 1920 joules of kinetic energy.

At what speed is she running?

• 5.66 m/s

• 8.00 m/s

• 32.0 m/s

• 64.0 m/s

Tags

CCSS.8.EE.A.2

The diagram shows a bicyclist at the top of a hill, with four points labeled W, X, Y, and Z.

Assume that the bicyclist does not apply the brakes as he rides down the hill.

At which point will the bicyclist’s kinetic energy be closest to zero?

• point W

• point X

• point Y

• point Z

The diagram shows a 155-newton box on a ramp. Applied force F causes the box to slide from point A to B.

What is the total amount of gravitational potential energy gained by the box?

• 28.4 J

• 279 J

• 868 J

• 2740 J

A person weighing 6.0 × 10² newtons rides an elevator upward at an average speed of 3.0 meters per second for 5.0 s. How much does this person’s gravitational potential energy increase as a result of this ride?

• 3.6 × 10² J

• 1.8 × 10³ J

• 3.0 × 10³ J

• 9.0 × 10³ J

Tags

CCSS.8.EE.A.4

Energy stored because of gravity is called:

• Gravitational Potential Energy

• Kinetic Energy

• Mechanical Advantage

• Chemical Energy

If W=Fd
Then how much work is done if it takes 20N to move a box 10 meters

• 0
• 2
• 20
• 200

At which point(s) on the roller coaster is the gravitational potential energy at its maximum?

• A
• B
• C
• D

In diagram 2, if the mass of the car is 600. kg, what is the change in potential energy from point A to point B?

• 400000 J

• 300,000

• 200000 J

• 100000 J