Download Newton`s Second and Third Law`s

Newton’s Second and Third Law’s
Ch 14
Main Idea:
As the net force acting on an object increases, the object accelerates
more.
1. What affects Acceleration?

Force and Acceleration-As a force increases, the acceleration also increases in the
same amount.


Ex: If you triple a force, the acceleration will also be tripled.
Mass and Acceleration- Doubling the mass of an object will decrease the acceleration.

Ex: If you tape two toy cars together (increasing the mass), the car will not go as
far.
2. Newton’s Second Law of motion:
F= m x a
3. How Is Acceleration Calculated?

Must know 3 things
1. starting speed
2. new speed
3. amount of time it took for change to happen

formula of accelerationo
a=F÷m
4. What are Balanced and Unbalanced Forces?
 Balanced forces- forces that cancel each other out when acting together on a single
object.
 Unbalanced forces- forces that do not cancel each other out when acting together on a
single object.
5. How Do Forces Act Between Objects?
 Action- the force one object applies to a second force
 Reaction- the force with which an object responds to an action
o Newton’s Third Law of motion- For every action, there is an equal
reaction.
6. What Is a Simple Machine?
 Work- using force to move an object
 Simple machine- a machine with few moving parts to make work easier.


Machines lower the force needed to move and lift heavy objects.
Levers- has a rigid bar that rests on a pivot point or fulcrum.

Fulcrum- pivot point

Effort arm- part of lever that applies force to the resistance arm

Resistance arm-lever part that applies force to the load the machine
acts against.

3 types of Levers
1.
first class
2.
second class
3.
third class
They differ in the position of their parts.

Wheels and Axles- a large wheel that rotates in a circle around an axle.

Pulleys- a wheel with a groove in the rim. A rope fits into the groove. It changes the
direction of the effort force. (fixed and moveable)
7. What Is an Inclined Plane?

A flat, slanted surface that makes it easier to move heavy objects to higher levels.

The slanted surface is the effort arm
o Wedges- an inclined plane that is used as a tool for cutting.
o Screws- an inclined plane wrapped in a spiral around a cylinder or cone