# Forces Force and Net Force Force is a

• Slides: 65

Forces

Force and Net Force • Force is a push or a pull on an object. • Net force is the total force on an object.

Unbalanced Force Balanced Force • Unbalanced Force can cause an object to move, stop moving, or change direction. • The balanced forces are the forces in equal and opposite directions.

Forces change motion.

Newton’s First Law Inertia – An object at rest Greater mass will stay at rest means unless acted upon by an outside force. Greater inertia – Inertia is every objects resistance to change its motion.

Newton’s Second Law • The acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to the object’s mass.

Force=mass x acceleration F=m x a • Or • a = Force/ mass • a = F/m

Equation for Newton It’s the same as the force equation! • Newton=m x a.

Force and mass determine acceleration.

Sometimes we might calculate mass using Force and Acceleration • Mass=Force/Acceleration • m=F/a

How much Force was required to make a 2000 kg car accelerate at 5 m/s? 1. 400 N 2. 0. 001 N 3. 10, 000 N

If you drop a 15 kg bowling ball with a Force of 147 N, what is it’s acceleration? 1. 9. 8 m/s/s 2. 0. 1 m/s/s 3. 2, 205 m/s/s

A person throws a baseball at an acceleration of 25 m/s/s with 12. 5 N of Force. What’s the Mass of the ball? 1. 312 kg 2. . 5 kg 3. 2 kg

4 Types of Friction • The 4 types of friction are: 1. Sliding friction (strongest) 2. Rolling friction 3. Fluid friction (weakest). 4. Static friction

• What type of friction?

• What type of friction?

• What type of friction?

What type of friction?

2 Factors of Friction • 1 -Type of surface. • 2 -How hard the two surfaces push together.

• Which type of hockey has more friction?

Air Resistance and Weight • Air resistance is a type of fluid friction on falling objects. Weight is the force of gravity on an object at the surface of the Earth.

Law of Universal Gravitation • Gravity acts between all objects in the universe.

Gravity Between Objects • The force of gravity between objects increases with greater mass and decreases with greater distance.

• Gravity is the force that pulls objects toward the Earthacceleration due to gravity is 9. 8 m/s/s.

Newton’s Third law • If an object exerts a force on another object, the second object, exerts an equal force in the opposite direction.

Momentum • The momentum of an object is the product of its mass and velocity. • In other words: Momentum = mass x velocity • Kg x m/s

COLLISIONS

Law of Conservation of Momentum • The total momentum of the objects that interact does not change.