What is a Force?

A force is any push or pull of an object to another object. Forces can be measured in Newtons and pounds.

A balanced force is a pair of forces that act on an object without changing it’s motion.

An unbalanced force is a force that changes an object’s motion.

Types of Forces

• Thrust-force that pushes object forward
• Lift-pushes object up
• Weight-pulls object down
• Drag-slows down object

In an airplane, the spinner provides the thrust, the gravity provides the weight, and the wings provide the lift. When the airplane is flying, the air is hitting the airplane and slowing it down, which causes drag. This is called air resistance.

What is Gravity?

Gravity is the force of the earth that pulls everything down to earth. Without gravity, nothing would be forced to stay put on the ground, and everything would float in air.

Friction

Friction is a drag force that is caused by and object rubbing across another object.

 

Newton’s Laws

1. Newton’s First Law
   • An object in rest tends to stay at rest and and object in motion tends to stay at motion, unless acted by and unbalanced force.
   • Inertia- the tendency of a moving object to keep moving in a straight line.
   • This law is related to inertia
2. Newton’s second law
   • The unbalanced force of an object is equal to it’s mass times it’s acceleration
   • F=M*A
3. Newton’s Third Law
   • All forces occur in pairs that are equal in strength and opposite in direction.
   • When one ice skater pulls on the other, they both feel the same amount of force.