Science 10 - Physics

Law of Conservation of Energy

The Law of Conservation of Energy states that…

Consider the following scenarios… (which take place in a “frictionless” world where no energy is lost to heat/sound etc.)

1. Dropping a soccer ball 2. Throwing a ball in the air

(v = 0m/s)

PE = 10 J KE = ______

PE = ______ KE = ______

PE = ______ KE = ______

The floor (h = 0 m)

2. Ball rolling down a hill 4. A swinging pendulum

KE = 10 J

(Assuming

her hand is at

height 0m)

V = 0m/s at the top

Law of Conservation of Energy Practice Worksheet

Answer the following questions and show your work!

1. Consider this ball rolling down a hill. Fill in the missing energy amounts.

2. Consider this basketball that has a mass of 0.6 kg. If it has 12 J at the top, what is the height?

(at the top) PE= 12 J, KE = ________

(at the halfwa y point) PE= ________ KE = ________

(on the floor) PE = _________ KE = _________

3. If this 30 kg child has a velocity of 4 m/s at the lowest part of the swing…

a. How much kinetic energy does she have at the lowest part of the swing?

b. How much potential energy does she have at the lowest part of the swing?

(assuming he just touches the ground at the base of the swing)

c. How much potential energy will she have at the highest part of the swing?

d. How much kinetic energy will she have at the highest part of the swing?

e. How high will the child be able to swing?

m = 30 kg

v = 4 m/s

4. Consider this 10 kg cart rolling up and down a hill.

a. If the cart is initially rolling at 5 m/s at the beginning,

how much kinetic energy does the cart initially have?

b. If the hill has a maximum height of 1 meter will the

cart make it over the top of the hill? (assume no

friction). (hint, how much PE does a cart at 1m have?)

c. When the cart is at the top of the hill does it have: (explain your answer)

i. Only Potential Energy?

ii. Only Kinetic Energy?

iii. Both PE and KE?

5. Try this Challenge Question!

Imagine there is a rollercoaster with a mass of 1 kg (just go with it ☺), fill in all the blanks for PE

(Potential Energy), KE (Kinetic Energy), and Total Energy (KE + PE) at the four different locations

on the ride. Also, can you figure out the height of the last hill?

m = 10 kg

V = 5 m/s

h =

1 m

m = 1 kg

Science 10 - Physics Name:

Physics Take Home Assignment: Conservation of Energy

Go to: http://phet.colorado.edu/get_phet/simlauncher.php

Open: “Energy Skate Park: Basics”

Click on the “Track Playground” tab

PART 1: Track Playground Ranking Tasks (friction turned off)

Do the ranking tasks below assuming no friction. Feel free to build if you are unsure!.

1. A) Rank the skateboarder positions A – G above in order of greatest potential energy to least

potential energy. Ties are possible.

___ ___ ___ ___ ___ ___ ___

B) Defend your answers.

2. A) Rank the skateboarder positions A – G above in order of greatest kinetic energy to least

kinetic energy. Ties are possible.

___ ___ ___ ___ ___ ___ ___

B) Defend your answers.

3. Actual skateboarders on a half-pipe often get a lot of “air” when they reach the other side

of the ramp. Explain how this is possible, if they’re starting at the same height as the other

side? (if you’re not sure, build a half-pipe and see if you can get the skateboarder to get

“air” and leave the ramp on the far side)