1. Physics!!!
UNIT 2:
FORCE AND MOTION

2. Warm Up (Silently) What is a force? What is an unbalanced force?
Skip one full page and then Write down the questions and answer them in complete sentences. Put your name, date, and period. It will be assignment number 1.
What is a force?
What is an unbalanced force?
What is a net force?

3. A force is a push or a pull that is capable of changing the velocity of a mass.
Forces are measured in “Newtons” or “N”, in honor of Sir Isaac Newton. According to Mr. Newton, an object will only accelerate if there is a “net force” acting upon it.

4. A net force is the sum of all forces acting on an object.
-- A net force is capable of accelerating or decelerate a mass.
Example. For instance, if the wheels of a car push it forward with 5 Newtons and drag is 3 Newtons, the net force is 2 Newtons, forward.
Motion to the right is positive. Motion to the left is negative. acceleration

5. As we have said before, a net force is the sum of all forces acting on an object.
Look at the picture of the red plane.
In this example, the difference between drag and thrust is 15 Newtons, to the left.
This net force is capable of accelerating (slowing down) the plane. Deceleration
Acceleration: Increase or decrease in speed.

6. What if the forces are balanced?
-Net force will be 0N
-The object will be:
At Equilibrium: not moving at all Or
Constant: moving at the same speed in the same direction and speed for eternity. (no friction, air resistance, etc.)

7. Unbalanced Forces: Placing a box on the seesaw unbalances it.
The weight of the box is the unbalanced or net force which causes the seesaw to accelerate downward until it hits the ground.

8. Let’s assume that the wheels of a car apply 10 N of force
Let’s assume that the wheels of a car apply 10 N of force. What is the net force if friction and drag are negligible?
What is the net force if the wheels of the car apply 10 Newtons but a parachute applies 7 Newtons in the other direction?
UNBALANCED FORCES

9. A rocket applies an additional force of 10 Newtons to the 10 Newtons that are applied by the wheels. What is the net force if the parachute continues to apply 7 Newtons in the other direction?

10. Balanced Forces: When forces are in balance, acceleration is zero
Balanced Forces: When forces are in balance, acceleration is zero. Speed is constant and there is no net or unbalanced force.
A plane will fly at constant velocity if the acceleration is zero.