Acceleration
What is a reference point?
A place or object used for comparison to determine if something is moving
An object is in motion when it changes position relative to a __________
reference point
Speed is the distance an object travels divided by __________.
time
A car travels 100 meters in 20 seconds. What is its speed?
5 m/s
Which situation describes an object moving at a constant speed?
A car travels 10 meters every second.
Which of the following can cause an object to accelerate?
Changing speed
Changing direction
Speeding up
Acceleration is a change in __________ over time.
velocity
A car traveling north turns east while keeping the same speed. Is it accelerating?
Yes, because its direction changed
If an object's velocity increases, the object is __________.
accelerating
Which measurement would be most useful for calculating speed?
A runner starts moving
If two objects travel the same distance, the object that takes less time has __________.
greater speed
An object that is not moving relative to its reference point is __________.
at rest
Projectile motion occurs when an object is __________.
launched into the air and moves under the influence of gravity
What force pulls a projectile toward Earth?
gravity
The path followed by a projectile is usually __________.
curved
A thrown baseball is an example of __________.
projectile motion
At the highest point of its path, a projectile still has __________ motion.
horizontal
What is the difference between speed and velocity?
Speed, No Direction Specified
Velocity, Specific Direction
What is a reference point when describing motion?
A reference point provides something to compare an object's position to so we can determine whether the object is moving
List three ways an object can accelerate.
What is negative acceleration?
Negative acceleration is acceleration in which an object's velocity decreases, such as when an object slows down.
Why does a projectile eventually fall back toward Earth?
Gravity pulls the projectile back toward Earth.
A runner travels 100 meters in 25 seconds. What is the runner's speed?
100 m ÷ 25 s = 4 m/s
A bicycle travels at 8 m/s for 5 seconds. How far does it travel?
8 m/s × 5 s = 40 m
A skateboarder slows from 12 m/s to 4 m/s in 4 seconds. What is the acceleration?
(4 − 12) ÷ 4 = −2 m/s²