Speed
What is speed?
How fast something is moving.
What is acceleration?
A change in speed or direction.
What does friction do to moving objects?
It slows them down or stops them.
What is the formula for speed?
Speed = Distance/Time
If a roller coaster goes from slow to fast, what is happening?
It’s accelerating.
What kind of surface has more friction: carpet or ice?
Carpet.
Marcos rides his bike for 2 hours and goes 60 miles. What is her speed?
30 miles per hour.
A soccer ball rolls across the grass and slows down. Is this still acceleration? Why or why not?
Yes, because acceleration means speeding up or slowing down.
What happens to the speed of a toy car when it rolls on carpet compared to a smooth floor?
It goes slower on the carpet because the carpet has more friction.
Two kids are racing. Jake runs 80 meters in 10 seconds. Lily runs 100 meters in 15 seconds. Who is faster, and how do you know?
Jake is faster.
A car is driving at 30 miles per hour and then speeds up to 50 miles per hour in 5 seconds. What happened to the car?
The car is accelerating because its speed is increasing.
Why is it harder to slide a heavy box than a light box?
Because the heavy box has more friction with the ground.
A car goes 50 miles in 1 hour, then 50 more miles in 2 hours. What is its average speed?
100 miles ÷ 3 hours = about 33.3 miles per hour.
A car speeds up from 10 meters per second to 30 meters per second in 4 seconds. What is the car’s acceleration?
the car’s acceleration is 5 m/s².
Why do cars have tires with bumps instead smooth tires?
The bumps create more friction, which helps the car stop easier when it needs to.