Motion occurs anytime an object changes its ______.
Position
Motion is entirely dependent on the ______ point.
Reference
Motion can be measured by distance, displacement, ______, velocity, and acceleration.
Speed
Velocity refers to an object’s ______ and direction.
Speed
Acceleration refers to the rate of change in an object’s ______ over time.
Velocity
An object can be moving at a constant speed and still accelerating if it is changing its ______.
Direction
When an object speeds up, it has a ______ acceleration.
Positive
When an object slows down, it has a ______ acceleration.
Negative
What’s the difference between distance and displacement?
Distance is the total path traveled; displacement is how far and in what direction from the start point.
What’s the difference between speed and velocity?
Speed is how fast an object is moving; velocity includes direction.
List three ways an object can accelerate.
- Speed up 2. Slow down 3. Change direction
If an object changes direction but keeps the same speed, is it accelerating? Why?
Yes, because acceleration is any change in velocity (and direction is part of velocity).
Can an object have zero displacement but nonzero distance? Give an example.
Yes. Example: walking in a circle and returning to the start.
A car starts from rest and accelerates at 3 m/s² for 6 s. What is its final speed?
v = 0 + 3×6 = 18 m/s
A train accelerates at 2.5 m/s² from 10 m/s for 8 s. What is its final speed?
v = 10 + 2.5×8 = 30 m/s
A bike speeds up from 5 m/s to 15 m/s in 4 s. What is its acceleration?
a = (15−5)/4 = 2.5 m/s²
A skateboarder slows from 12 m/s to 4 m/s in 2 s. What is her acceleration?
a = (4−12)/2 = −4 m/s²
A cart rolls down a hill with an acceleration of 3.5 m/s² for 6 s. Starting at 2.0 m/s, what is its final speed?
v = 2 + 3.5×6 = 23 m/s
A race car starts at 20 m/s and accelerates at 5 m/s² for 4 s. (a) What is its final speed? (b) How far does it travel?
(a) v = 20 + 5×4 = 40 m/s (b) d = 20×4 + 0.5×5×4² = 120 m
