1. Forces and Motion
Notes

2. Motion = Change in position in a certain amount of time.
Force = Push or pull that gives energy to an object causing it to start moving, stop moving, or change direction.
Friction = Force that slows down an object because it is moving in the opposite direction.
Gravity = Force of attraction between objects that is due to their masses.

3. Time Forces and Motion Speed = Rate of motion Speed = Distance Time
Speed = Rate of motion
Speed = Distance
Time
Velocity = Speed in given direction
V = Distance Direction
Time

4. Acceleration = Force/Mass
Acceleration = Rate at which velocity changes.
Ex: when you increase your speed to escape a dog running after you, you are accelerating.
Acceleration Formula
Acceleration = Force/Mass
Even falling objects have acceleration due to gravity.
Gravity (g) = 9.8 m/s2

5. Calculating Speed and Velocity
1. John traveled 1000 meters to the grocery store in 500 seconds. What was the speed at which he was traveling?
Speed = Distance
Time
= meters
500 seconds
= 2 m s
2. Melanie drove west from Bastrop to Barton Creek Mall in Austin. The mall is 40 miles away and it took her 1 hr. What was her average velocity?
Avg Vel = Ttl Distance Dir
Ttl Time
= 40 miles west
1 hour
= 40 mi west hr

6. NEWTON’S LAWS OF MOTION
Newton’s 1st Law = An object at rest will stay at rest & an object in motion will stay in motion unless acted upon by an external force.
Ex: The car stops suddenly & your body lurches forward.
Inertia = The tendency of all objects to resist any change in motion.
Ex: Your body at rest, a train coming down the track

7. NEWTON’S LAWS OF MOTION
Newton’s 2nd Law = Acceleration is produced when a force acts on a mass.
The greater the mass of the object, the greater the amount of force needed to accelerate the object.
The greater the acceleration needed, the greater the amount of force needed to move the mass.

8. NEWTON’S LAWS OF MOTION
Force = mass X acceleration
F = m X a
acceleration = Force / mass
a = F / m
The unit for Force is Newtons (N)

9. NEWTON’S LAWS OF MOTION
Newton’s 3rd Law = For every action there is an equal and opposite reaction. All forces act in pairs!!
Example: There is no air in space. So how does the space shuttle travel in space?
Answer: The shuttle engines push the exhaust gases downward as the gases push the shuttle upward with an equal force.