WHAT IS A FORCE A force is a

WHAT IS A FORCE? ? ?

A force is a push…. . PUSH

PULL … or a pull

U P H S

PULL

FORCES Weight Magnetism Friction Gravity Thrust NOT FORCES Mass Inertia Speed Acceleratio n Velocity

Y T I V A R G S I T E N G MA M WEIGH T

FRICTIO N When an object moves in one direction, sliding past another object, friction moves it in the

THRUST Thrust is a strong push that quickly moves an object

Forces are measured in units called Newtons (N) 100 N

NET FORCE is the combining of ALL forces on an object • Each person is putting a force on the rope!

Forces moving in opposite directions are subtracted 20 N 10 N NET FORCE ON THE CAR =

30 N 15 N NET FORCE ON THE TOY = 15 N

Forces moving in the same direction are 12 N added 12 N NET FORCE ON THE CAR = 24

Newton’s Motion st 1 Law of Objects at rest remain at rest, objects in motion remain in motion with the same speed and direction, unless acted on by an unbalanced force.

What is a balanced force?

BALANCED FORCES • All forces acting on an object are equal and opposite in direction. • Net force equals zero • Causes no change in motion of the object

20 N BALANCE NET FORCE = D 0 N NO MOVEMENT!!!!!

20 N NET FORCE ON THE CAR= 0 N THERE WILL BE NO

UNBALANCED FORCES • All forces acting on an object are NOT equal • The net force will NOT be 0 N • There WILL be a change in motion

• The force of the boys pushing on the car, is greater than the force of friction. 24 N • The forces are unbalanced. FRICTIO N 4 N What is the NET FORCE? Which direction will the car

50 N 10 N

Which way is this car going to move? 100 N 10 N

Objects at rest remain at rest until acted on by unbalanced forces. The apple is at rest GRAVITY makes it fall

The soccer ball remains at rest, until someone exerts thrust on it by kicking it.

Objects in motion remain in motion with constant speed and in the same direction, until acted on by an unbalanced force.

INERTIA- An object’s resistance to a change in its path of motion IN OTHER WORDS…INERTIA IS WHEN AN OBJECT DOES NOT WANT TO SPEED UP, SLOW DOWN, OR CHANGE DIRECTION!!!

When the bike hits the rock, it will sto INERTIA says the boy will resist a change in motion and keep moving. He goes flying over the handle bars

The skateboarder is moving at a constant speed and direction. He will eventually stop because of the force of friction acting on the wheels. FRICTION

• The car is in motion, until acted on by the wall. • The wall has more force than the car, so it will be stopped

The pitcher throws a baseball in a certain pathway. The batter exerts a thrust on the ball with the bat, and the ball changes direction.

When the baseball is hit by the batter, it flies in the air. INERTIA says that it will stay moving in the same path at the same speed. GRAVITY forces the ball to change it’s path.

This plane has a constant airspeed. • When a force (THRUST) is acted on it, the airspeed will increase, and the plane will • If a different force (DRAG) is acted on it, the airspeed will decrease, and the plane will

Newton’s Motion nd 2 Law of Force (F) = mass (m) x acceleration (a)

Newton’s Motion rd 3 Law of For every action, there is an equal and opposite reaction.