1. Objective 4 Review
The student will demonstrate an understanding of motion, forces, and energy.

2. Energy Transformations
Energy is the ability to do work or cause change.
The sun sends energy to Earth in the form of electromagnetic waves (light).
We then convert the sun’s energy into different types of energy that we use everyday.
Energy travels in waves.

3. Types of Energy Sunlight Chemical Electrical Sound Mechanical Heat
Produced by nuclear fusion in the sun and then transmitted to Earth.
Chemical
Held in the bonds between atoms and is released during a chemical reaction.
Electrical
Created by burning fossil fuels or using water (hydroelectric). Produced by electrons flowing through a conductor.
Sound
Mechanical energy created by a vibrating object. Must travel through a medium.
Mechanical
The energy of an object due to its position or motion.
Heat
Objects absorb energy through conduction, convection or radiation.

4. Types of Energy

5. Energy transformations occur in many different ways
Energy transformations occur in many different ways. Which of the examples given is an example of chemical energy transforming into heat and light?
Eating an apple and then running
Using a gas lantern
Sunlight shining on a thermometer
Fire boiling soup
TMSDS 6.9A

6. Energy POTENTIAL Stored energy due to an object’s position KINETIC
The energy an object has due to its motion. 1.
½ KINETIC and ½ POTENTIAL – The object is halfway down the hill.
POTENTIAL Energy – The object is high above the ground. 2. 3.
KINETIC Energy – The object is moving at is fastest speed.

7. Which choice is an example of kinetic energy changing into potential energy?
A person climbs to the top of a slide.
A television is turned on.
A breeze moves a flag.
A tree branch falls to the ground.
TMSDS 7.8A

8. Monique rode the roller coaster at her local amusement park
Monique rode the roller coaster at her local amusement park. The ride took her over many hills and through loops. Look at the image of the roller coaster below. At which point was Monique’s potential energy the greatest? A B C D
TMSDS 7.8A

9. Forces A force is a pushing or pulling action.
Forces can move objects or transfer energy between objects.
Living things use force to move.
We show forces using → and use the unit Newton (N).
Common forces: gravity, friction, air pressure, buoyant force of water (floating)

10. Motion
Motion is the change in position of an object. Anything that is moving is in motion.
Objects that are NOT in motion have BALANCED FORCES acting on them.
In order for a force to move something, it must be an UNBALANCED FORCE.

11. Forces and Motion Q: Which Team will win?
A: Neither. The forces are BALANCED.
Team 2
Team 1
Q: Which Team will win?
A: Team 2. They are pulling with a larger force.

12. Imagine a bat swinging with a force of 1,000 N hitting a ball pitched with a force of 200 N. At what net force does the ball move away from the bat?
1,200 N
800 N
600 N
Net force zero
TMSDS 6.6

13. It will move 20 N to the right. It will move 20 N to the left.
A hot air balloon is floating in the air. There are many forces acting on it, but the Net Force of the balloon when there is no wind equals zero. How will the balloon most likely move if the wind shown in the diagram occurs?
It will not move.
It will move 20 N to the right.
It will move 20 N to the left.
It will move to the ground.
TMSDS 6.6

14. Marita is riding her bicycle directly south at a speed of 10 kilometers per hour (km/hr). A strong gust of wind suddenly exerts a large force on the bicycle. Marita continues moving south but slows to 6 km/hr. Which of the following is a correct description of the force and direction of the gust of wind?
The force of the wind acted south and was less than Marita’s forward force.
The force of the wind acted north and was less than Marita’s forward force.
The force of the wind acted south and was greater than Marita’s forward force.
The force of the wind acted north and was greater than Marita’s forward force.
TMSDS 7.6A

15. What is required to change the direction of a moving object?
an unbalanced net force on the object
a balanced net force on the object
several forces acting in the same direction
no force on the object
TMSDS 8.7A

16. Calculating Speed SPEED = DISTANCE / TIME
During a baseball game the batter has to run to first base. First base is 12 m away from home plate. It takes the runner 6 seconds to get there. What is the speed of the batter?
Distance = 12 m
Time = 6 s
Speed = 12 m / 6 s = 2 m/s
A semi-truck is traveling down the highway at a speed of 60 m/s. It takes the truck 10 minutes to arrive at its location. How far did the truck travel?
Time = 10 min = 600 s
Speed = 60 m/s
Distance = Speed x Time
= 60 m/s x 600 s = 36,000 m

17. Graphing Speed

18. A ball travels north at a rate of 5 meters per second
A ball travels north at a rate of 5 meters per second. If a southward force starts acting on the ball, which will happen FIRST?
Its northward speed will increase.
Its northward speed will decrease.
It will stop moving.
It will start traveling south.
TMSDS 8.7A

19. Calculating Force and Motion
Force = Mass x Acceleration
Work = Force x Distance
A student weighing 50kg rides a skateboard that weighs 2kg. You begin rolling with an acceleration of 2 m/s2. What is the force used to make the skateboard move?
Mass = 50kg + 2kg = 52kg total
Accelaration = 2 m/s2
Force = 52kg x 2 m/s2
= 104 kg . m/s2 = 104 N
In order to clear a lot, a large rock must be moved to a new location. How much work must be peformed to move the rock with a force of 100N a distance of 5 m?
Force = mass x acceleration = 100N
Distance = 5 m
Work = 100 N x 5 m = 50 N.m

20. A student weighing 100kg rides a bike that weighs 10kg
A student weighing 100kg rides a bike that weighs 10kg. You begin rolling with an acceleration of 10 m/s2. What is the force used to make the skateboard move?
9 N
1 N
11 N
6 N

21. In order to clear a lot, a large tree must be moved to a new location
In order to clear a lot, a large tree must be moved to a new location. How much work must be peformed to move the tree with a force of 2000N a distance of 100 m?
20 N.m
1990 N.m
2000 N.m
20,000 N.m

22. REMEMBER: Simple Machines make work easier!
REMEMBER: Simple Machines make work easier!

23. Types of Waves
Electromagnetic = can travel through space (nothing!) or a medium
Mechanical = must travel through a medium
Transverse
the wave moves through and causes the object to move up and down (jump rope)
Compressional
the wave moves through and causes the object to move in the same direction (slinky)

24. Frequency – the time it takes for the wave to complete one cycle
Measuring Waves
Frequency – the time it takes for the wave to complete one cycle

25. When an earthquake occurs, waves are generated and cause vibrations
When an earthquake occurs, waves are generated and cause vibrations. The waves are able to cause vibrations far from the center of the earthquake because of their ability to travel in which medium?
rock
water
air
a vacuum
TMSDS 8.7B

26. A teacher tapped a metal rod with a mallet in science class and produced a sound. What caused that event to occur?
A current began to flow.
Magnetic poles are reversed.
Waves were generated.
Ions were released.
TMSDS 8.7B