Forces and Motion

Monday, September 16, 2013Mrs. HensleySedgefield Middle School

DO NOW!

In your scientific journal, please describe a recent dream you have. Provide as much detail as possible.

5 minutes.

Force and motion

Continue taking notes in your scientific journal.

A force is a push or pull on an object.

It can either cause it to start moving, change direction or slow down until it finally stops.

Forces

Always act in pairs.

Balanced forces

Are opposite in direction and equal in size which causes no change in motion.

Balanced Forces have NO MOTION

Unbalanced forces

Cause a change in motion

Unbalanced forces have MOTION

Speed

Measures how fast an object is traveling.

Velocity

Measures how fast something is traveling in a direction.

This skydiver has velocity because he is falling at a constant speed and in a specific direction…DOWN!

Acceleration

A change in speed or direction.

Acceleration and deceleration

A constant change of speed, slowing up or slowing down.

Friction (substitute, please read)

For an object in motion will continue to keep moving at a constant velocity unless acted on by an outside force. In real world situations, what causes an object to come to a stop is a force that will oppose the motion (friction). When objects are in contact with each other, friction will act in the direction opposite to the motion and change the motion of the moving object.

Discovery Education Video

http://app.discoveryeducation.com/search?Ntt=gravity+and+friction

Gravity (substitute, please read)

Gravity is a universal force that causes objects to be attracted to each other. When no other outside force, such as friction or air resistance, acts upon a falling object, its speed increases. An object constantly gains speed for every second it falls until it reaches a maximum speed, which differs depending upon the shape of the object and the friction with the air.

Sir Isaac Newton

Sir Isaac Newton is credited with describing laws of gravity and motion. His three laws of motion explain objects at rest, constant motion, and acceleration due to balanced or unbalanced forces exerted on objects.

First Law of Motion

The first law describes inertia, the tendency of an object to remain in motion or stay at rest.

Second Law of Motion

The second law explains the dynamics of unbalanced forces

Third Law of Motion

The third law notes that for every action (force), there is an equal and opposite reaction.

Newton’s Laws video

http://app.discoveryeducation.com/search?Ntt=newtons+laws

Machines (substitute, please read)

People use simple and complex machines to perform “everyday” tasks, which require a force to move objects. The amount of effort saved when using machines is called mechanical advantage. Machines can make work seem to be easier by changing the size or direction of an applied force. Each machine makes work easier by providing some trade-off between the force applied and the distance over which the force is applied. Through a better understanding of forces and motion, scientists and engineers have been able to design more efficient systems related to sports, recreation, transportation and human health.

Simple Machines video

http://app.discoveryeducation.com/search?Ntt=machines&N=18342&N=4294949582

Six Simple Machines

1. Pulley2. Lever3. Inclined Plane4. Wedge5. Wheel and axel6. Screw

Exit Ticket

In your journal, give an example of each of the 6 simple machines.