Physics: Forces and Motion: Speed, Velocity, Acceleration
Describe and calculate how objects move
Physics: Forces and Motion: Speed, Velocity, Acceleration
Describe and calculate how objects move
Physics - Grade 4-5
- 1
A student walks 20 meters in 10 seconds. What is the student's speed?
Speed equals distance divided by time.
The student's speed is 2 meters per second because 20 meters divided by 10 seconds equals 2 meters per second. - 2
A toy car moves 15 meters east in 5 seconds. What is its velocity?
Velocity includes both speed and direction.
The toy car's velocity is 3 meters per second east because 15 meters divided by 5 seconds equals 3 meters per second, and velocity includes direction. - 3
Circle the example that shows acceleration: a bike moving at the same speed in a straight line, a skateboard slowing down, or a book sitting on a desk. Explain your choice.
A skateboard slowing down shows acceleration because acceleration means a change in motion, including speeding up, slowing down, or changing direction. - 4
A runner travels 40 meters in 8 seconds. Calculate the runner's speed.
Divide the total distance by the total time.
The runner's speed is 5 meters per second because 40 meters divided by 8 seconds equals 5 meters per second. - 5
Two scooters are moving. Scooter A travels 30 meters in 10 seconds. Scooter B travels 30 meters in 5 seconds. Which scooter has the greater speed, and why?
Scooter B has the greater speed because it travels the same distance in less time. Scooter A moves 3 meters per second, and Scooter B moves 6 meters per second. - 6
A ball rolls north at 4 meters per second. Write this motion as a velocity.
Do not forget to include the direction.
The ball's velocity is 4 meters per second north because velocity includes the speed and the direction of motion. - 7
A car starts from rest at a stop sign and begins moving faster. Is the car accelerating? Explain your answer.
Yes, the car is accelerating because its speed is increasing from rest to a faster speed. - 8
A dog runs 24 meters in 6 seconds. What is the dog's speed?
Use the formula speed = distance divided by time.
The dog's speed is 4 meters per second because 24 meters divided by 6 seconds equals 4 meters per second. - 9
A cyclist travels west at 7 meters per second. Is 7 meters per second the cyclist's speed or velocity? Explain.
7 meters per second by itself is the cyclist's speed. The full velocity is 7 meters per second west because it includes direction. - 10
A soccer ball is kicked and changes direction when it bounces off a wall. Did the ball accelerate during the bounce? Explain.
Acceleration can mean changing direction, not only speeding up.
Yes, the ball accelerated because changing direction is a change in velocity, even if its speed stays about the same. - 11
A train travels 100 meters in 20 seconds. What is the train's speed?
The train's speed is 5 meters per second because 100 meters divided by 20 seconds equals 5 meters per second. - 12
Which statement describes velocity: The turtle moves slowly, the turtle moves 1 meter per second east, or the turtle is green? Explain your answer.
Look for a speed and a direction together.
The statement 'the turtle moves 1 meter per second east' describes velocity because it gives both speed and direction. - 13
Look at a distance and time table for a cart: after 1 second it has gone 2 meters, after 2 seconds it has gone 4 meters, after 3 seconds it has gone 6 meters, and after 4 seconds it has gone 8 meters. What is the cart's speed?
The cart's speed is 2 meters per second because it moves 2 meters during each second. - 14
A bus is moving at 10 meters per second and then slows to 5 meters per second as it approaches a stop. Is this acceleration? Explain.
Any change in speed is acceleration.
Yes, this is acceleration because the bus's speed changes. Slowing down is a type of acceleration. - 15
A paper airplane flies 12 meters south in 4 seconds. Find its speed and its velocity.
Find speed first, then add the direction for velocity.
The paper airplane's speed is 3 meters per second because 12 divided by 4 equals 3. Its velocity is 3 meters per second south because velocity includes direction.