MATTER IN MOTION

SPEED

• Speed is the distance traveled by an object divided by the time taken to travel that distance
• Formula = speed/distance S = d/t
• Fun fact:cheetahs can accelerate from 0 to 70 km/h (43mp/h) in 3 seconds
• example - what is the speed of a chicken if it travels 20 m in 5 sec?
• Answer - 4m/s

AVERAGE SPEED

• average speed of an object is defined as the distance traveled divided by the time elapsed.
• Formula - Total distance over total time AS = td/tt
• Fun fact: A man walks 3 miles per hour or 4 feet per second
• example - The dog walked slowly at first, then moved fast for 1 sec. The dog didnt move for the next 3 sec. The last 4 sec it walked with speed
• Answer - Avergage speed = 7m/10s = 0.7 m/s

VELOCITY

• Velocity is the speed of an object in particular direction
• Formula - Velocity = distance over time V = d/t
• fun Fact: Escape velocity is the minimum velocity a body must have in order to escape from the gravitational field of the earth.
• example - as a bus at 15m/s speeds up to 20m/s south its velocity changes, it keeps changing

ACCELERATION

• Acceleration is the rate at which velocity changes over time
• Formula - Acceleration Velocity over time A = v/t
• Fun fact: The acceleration of Earth's gravity will speed you up at about 9.8 meters per sec
• example - A bike accelerates uniformly from rest to a speed of 7.10 m/s over a distance of 35.4 m. Determine the acceleration of the bike.
• Answer - 0.712 m/s

NET FORCE

• net force is the overall force acting on an object
• Formula - net force mass times acceleration F = ma
• Fun fact: we excert a force on a book when we push it with our hand
• example - You and your friend are moving a piano, you push one end, the forces you snd your friend excert on piano act in same direction