Force and motion notes

Force  Push or pull Net Force  The overall force  Add the forces together

Speed Distance an object covers in a period of time Formula = distance / time Units distance: m, cm, mm, in, yd, mi, km time: sec, hr, yr, week, month speed: m/hr, mi/sec, ft/yr

Reference point Object/location you compare to determine if something is moving Example- leaving your driveway

Average speed The average of all speeds on a given trip (most objects speed up and slow down during a trip) Total distance/total time

Average Speed

Constant speed The speed must stay the same the entire time Using cruise control in your car

Velocity Tells both the speed and direction that an object moves Example- the car is traveling 50 miles/hour west

Velocity of Passing Line

Acceleration Tells how the velocity changes  Speeding up  Slowing down (deceleration)  Changing direction

Constant Speed vs. Acceleration Observe the animation of the three cars below. Which car or cars (red, green, and/or blue) are undergoing an acceleration? Study each car individually in order to determine the answer.

Motion Process of moving from one place to another Everything in the universe is moving- your senses do not tell you that the earth is moving because it is moving at great speed

Balanced Forces- will NOT change the object’s motion

Unbalanced Forces- causes an object to start moving, stop moving, or change direction

The 5 types of forces 1. friction 2. contact force 3. gravitational force 4. magnetic force 5. electrical force

Friction force that one object applies on another. The rougher the surfaces, the greater the friction will be produces heat Air resistance Example- Kicking a soccer ball, the grass is the friction force.

Contact Force two objects are touching, they push each other away. Example- Pushing a child on a swing.

Gravitational Force force between all objects in the universe Weight

Magnetic Force Force that exists between metals North pole and south poles attract

Electrical force Results from moving electrons electricity

Newton’s Laws of motion Sir Isaac Newton lived during the 1600s

Newton’s 1 st Law An object in motion will stay in motion and an object at rest will stay at rest unless acted on by an unbalanced force. Inertia

Newton’s 2 nd Law Force = Mass x Acceleration Gravity accelerates all objects at the same rate, so the elephant and the rock would hit the ground at the same time. (only in a vacuum effect) The difference in forces would be caused by the different masses.

Newton’s 3 rd Law For every action there is an equal and opposite reaction. Newton’s cradle- toy The skaters' forces on each other are equal in magnitude, and in opposite directions