VS. Not all things move in a consistent, “uniform” way… . Uniform and Non-uniform Motion. When a body covers equal distances in equal intervals of time then the body is said to describe uniform motion . Uniform Motion.
A change in velocity ( ) occurs when the speed of an object changes and/or its direction of motion changes.
A change in velocity can be calculated by:Changing velocity…
= change in velocity
= final velocity
Case 1: If the change in velocity is the same sign (+, -) as the initial velocity, the speed of the object is increasing!
The initial velocity and the change in velocity are both positive, so the car is speeding up!
Case 2: If the change in velocity is the opposite sign (+, -) of the initial velocity, the speed of the object is decreasing.
The initial velocity is positive and the change in velocity is negative, so the shuttle is slowing down !
Case 3: If the change in velocity is zero, the object is travelling with uniform motion!So what do these numbers mean???
THE ROCKET CAR!!!
… OK… maybe not… just a cool clip!!!
This change in velocity can be due to a change in speed and/or a change in direction.
Two objects with the same change in velocity can have different accelerations.
This is because acceleration describes the rate at which the change in velocity occurs.Acceleration!
Suppose both of these vehicles, starting from rest, speed up to 60 km/h. They will have the same change in velocity, but, since the dragster can get to 60 km/h faster than the old car, the dragster will have a greater acceleration.
The direction of the acceleration is the same as the direction of the change in velocity.
Acceleration that is opposite the direction of motion is sometimes called deceleration… but as of Physics 11 most teachers will refer only to acceleration!Positive and negative Acceleration