Effects of Forces• Change shape

Effects of Forces• Change shape

Change of Shape

extensionForce is directly proportional to

extension

Force is directly proportional to extension

• When force doubles, the extension doubles

• F α x Fx

= constant

Hooke’s Law

Force is directly proportional to extension

F1

x1

=F2

x2m1

x1

=m2

x2

What if we put more weights than we did?

Limit of proportionalitySee p.23 SQ and Key Points See p.29 question 5

Effects of Forces• Change the state of motion

– Move from rest– Speed up– Slow down – Stop– Change its direction

Balanced forces

Balanced Forces

The book stays still!

Balanced Forces

The airplane moves forwards at constant speed!

Balanced Forces

The car moves at constant speed!

Drag

Friction

Thrust

Unbalanced Forces

The car moves from rest.

The car speeds up.

Unbalanced Forces

The car slows down to stop.

The car slows down.

See p.25 SQ and Key Points See p.27 SQ and Key Points