U1 Motion and Forces

Acceleration

• Measures a rate of change in VELOCITY
• Rate at which velocity CHANGES

Acceleration

• An object is said to accelerate if its SPEED, DIRECTION of motion, or BOTH change
• Depends on velocity change and amount of time that the change took place

Calculating Acceleration

• Average Acceleration = (final velocity - starting velocity) / time

Accelerating & Speed

• Acceleration can mean an object INCREASES or DECREASES in speed

Positive Acceleration

• Going from a small velocity to a large one is called POSITIVE ACCELERATION
• Ex. Sliding down a hill

Negative Acceleration

• A decrease in velocity is called NEGATIVE accleration
• Ex. Race car slowing (high velocity to low velocity)

Acceleration and Direction

• When acceleration and speed are in the SAME direction the speed will INCREASE
• When acceleration and velocity are OPPOSING directions speed will DECREASE

Acceleration and Direction

• Objects can accelerate without change in speed because change in DIRECTION
• Acceleration in a circular motion is CENTRIPETAL ACCELERATION