# Linear Motion – Velocity / Acceleration ```Linear Motion – Velocity / Acceleration
What is velocity?
What is constant velocity?
If a car is traveling in a circle, is it maintaining constant velocity?
What is changing velocity?
What is acceleration?
*Acceleration, like velocity is directional. If we change speed, direction, or
both, we accelerate.
Acceleration = change of velocity / time interval
or
Acceleration (along a straight line) = change of speed / time interval
For Example: 300 km/h / 1 s = 300 km/h&middot;s
Note: The acceleration is 300 km/h&middot;s
Which is read as “300 kilometers per hour-second”
What is deceleration?
Problems:
1. Suppose a car moving in a straight line steadily increasing its speed each
second, first from 35 to 40 km/h, then from 40 to 45 km/h, then from 45 to 50
km/h. What is its acceleration?
2. In 5 seconds a car moving in a straight line increases its speed from 50 km/h
to 65 km/h, while a truck goes from rest to 15 km/h in a straight line. Which
undergoes greater acceleration? What is the acceleration of each vehicle?
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