1. Force and Motion

2. Potential vs. Kinetic Potential Kinetic * GPE * KE
* stored energy * energy of motion
* not moving * moving
* the higher the object * the faster an object
the more PE the more KE
* GPE=mgh * KE=mv2
G= 9.8 m/s2

3. Mechanical vs. Chemical
Mechanical Chemical
ME = PE+KE
Physical change * Chemical change
Only changes the physical * changes the appearance composition
Ex. Gears moving in a car * Ex. food being broken down
Energy that is moving * energy that is stored

5. Sample Question
A 21.7 kg ball is located on a shelf 1.6 m above the ground. Which best describes the energy of the ball?
Its energy is lost once it falls off the shelf
Its energy depends upon the speed the ball will travel
It has mechanical energy in the form of potential energy
It has mechanical energy in the form of kinetic energy

6. Sample Question
What happened to the ball’s energy from Point 1 to Point 4?
Stored Energy was transformed into energy of motion
Energy of motion was transformed into chemical energy
Stored energy in the ball applied a force to get the ball to move
Internal energy caused the ball to move until the energy was gone

7. Sample Question
As a roller coaster car travels down a hill, which type of change in energy allows it to speed up?
A. Potential energy changing into heat energy
B. Potential energy changing into kinetic energy
C. Kinetic energy changing into heat energy
D. Kinetic energy changing into potential energy

8. Types of Energy
Electrical: energy that is transferred by electrical charges or current
Sound: associated with vibrations of matter and requires an object to travel through (Medium). Ex. Water
Solar: the energy given off by the sun
Chemical: energy that is stored in the chemical composition of matter
Thermal: the energy given off by heat
Light: energy given off by light
Nuclear: the potential energy stored in the nucleus of an atom

9. Sample Question
What form of energy does a car’s engine convert into mechanical energy?
Light
Wind
Chemical
Gravitational

10. Sample Question
Which type of energy is changed by plants into chemical energy? A. Solar B. Nuclear C. Thermal D. Gravitational

11. Simple Machines Type Definition Example Illustration Lever
Inclined Plane
Pulley
Wheel & Axle
Wedge
Screw
A solid bar that rotates around a fulcrum
Wheelbarrow
Handicap ramp
A flat horizontal or sloped ramp
Crane, gears
A wheel that turns on an axle
Car or gears
A wheel that is fixed to a pulley
2 incline planes that are together
screwdriver
Spiral stairs or meat grinder
An incline plane wrapped around a shaft

12. Sample Question How can an inclined plane make work easier?
By increasing the amount of friction necessary for the task
By increasing the effort necessary to raise an object
By decreasing the effort required to raise an object
By decreasing the efficiency of the task

13. Sample Question
Which simple machine would be the most efficient for lifting an object 30m off the ground?
Pulley
Screw
Wedge
Lever

14. Force and Motion Important Terms
Position: location (can be an object or place)
Reference Point: location that you compare your object or place’s position
Motion: change of position over time

15. Forces and Motion Terms
Speed: the measure that something moves in a given amount of time speed=distance/time
Velocity: speed in a specific direction velocity=distance/time
Acceleration: the rate at which velocity changes with time acceleration=velocity final- velocity initial/time

16. Force and Motion Important Terms
Friction: force that resists the motion between two surfaces in contact.
Force: a push or pull (F= M x A)
Balanced force: net force is zero, the motion of an object does not change
Unbalanced force: changes the motion of an object
Inertia: the resistance of an object to a change in the speed or direction of its motion

17. Newton’s 1st Law of Motion
An object at rest stays at rest, and an object in motion stays in motion at the same velocity, unless acted upon by an unbalanced force.
Newton’s First Law is also called the Law of Inertia.
Inertia is closely related to mass. When you measure the mass of an object, you are also measuring its inertia.
The more mass something has, the harder it is to change its motion.
Ex: It’s easier to stop an empty wagon than a wagon full of sand.

19. 2nd Law of Motion
Acceleration of an object increases with increased force and decreases with increased mass.
The direction in which an object accelerates is the same as the direction of the force.
Simply put: Newton’s Second Law is…
F = ma
(Force = mass x acceleration)
The standard unit of force is the newton (N).
Because force = mass x acceleration, force is measured in units of mass (kg) times units of acceleration (m/s2).
A newton is the amount of force that it takes to accelerate 1 kg of mass 1 m/s2.
So…. I N = 1 kg x 1 m/s2.

20. Sample Question
John wants to build a racetrack that will allow his toy cars to travel fast when force is applied. Which material should be use?
carpet, because friction will be high
Gravel, because friction will be high
Plastic, because friction will be low
Sandpaper, because friction will be low

21. 3rd Law of Motion Forces always act in pairs!
Newton’s Third Law: For every action, there is an equal and opposite reaction.
Every time one object exerts a force on another object, the second object exerts a force that is equal in size and opposite in direction back on the first object.

23. Sample Question
A magnet is placed near a pile of steel paper clips. Which will most likely occur?
The magnet will provide a balanced force, causing the paper clips to spin in circles.
The magnet will provide an unbalanced forces, keeping the paper clips stationary.
The magnet will provide a balanced force, pushing the paper clips away from it.
The magnet will provide an unbalanced force, pulling the paper clips toward it.

24. Summary of Newton’s 3 Laws

25. Distance/Time Graphs
The motion of an object can be represented in a line graph. The data table below charts the motion of an object in 20 seconds.
Construct a line graph on page 28 (blank page) that shows the motion of the object. Be sure to label both axes.
Then, use the graph to describe the motion of the object between 0 and 10 seconds.
Distance vs. Time
Time (s)
Distance (m) 5 10 15 20

26. Sample Question Which describes their motion?
Steven threw four balls into the air and recorded their heights. The chart below shows the maximum height for each ball.
Ball P went twice as high as Ball N
Ball M went twice as high as Ball N
Ball P went two meters higher than Ball O
Ball N went two meters higher than Ball O
Ball
Maximum Height (m) M
2.0 N
1.5 O
4.2 P
3.0

27. Sample Question
The chart shows the distance traveled by an object over 100 seconds.
What happened to the motion of the object between t=50s and t=70s?
The object increased its speed
The object decreased its speed
The object stopped moving
The object changed directions

28. Sample Question
Which graph represents a moving object with a constant speed throughout its entire travel time?