Physics Test Review Key

Physics Test Review Key

8.6A and 8.6B

Balanced and Unbalanced Forces

1. Define balanced force:If the net force is zero, the forces are balanced and the object stays still (at rest) or a constant speed

Give an example of a balanced force in real life:A racer going 100 miles per hour at a constant speed

1. Define unbalanced force: If the net force is not zero, the objects motion and acceleration will change

Give an example of an unbalanced force in real life:A car accelerating past a stop sign.

1. An unbalanced force causes _____acceleration______.

1. Fill in the chart below by choosing words from the word bank and deciding if they should go with the term balanced or unbalanced force:

1. Explain what the following terms mean:
2. Friction:A force between two surfaces rubbing against each other; friction works against motion

1. Motion:Movement of an object relative to another point

1. For each of the diagrams below, calculate the net force and describe how the motion of theobject will change.

Speed, Velocity, and Acceleration

1. Define the following words:
2. Speed: How fast an object is moving, must have both distance and time

1. Velocity:Speed (distance and time) of an object plus its direction

1. Acceleration:Change in velocity; An object is accelerating if it speeds up, slows down, OR changes direction

1. Fill in the chart below by choosing words from the word bank and deciding if they should go with the term speed, velocity, or acceleration. WORDS CAN BE USED MORE THAN ONCE:

1. What is the biggest difference between speed and velocity?Both of them include distance and time, but velocity also includes direction.

1. Label the following examples as speed, velocity, or acceleration:

1. ____Velocity______: A subway travel East at 45 km/hr
2. ___Speed______: A 1 kg marble rolls a distance of 35 feet in 20 seconds
3. ____Speed______: Sally runs 7 km/h for 25 minutes
4. ____Acceleration______: A runner slows to a stop as he gets tired

Speed Graphs

1. Based on the graph, match the appropriate description to letter on the graph.

The graph below shows the distance traveled by a ball. Use the graph below to answer question 12 – 18.

1. According to the graph, between 0 and 2 seconds the ball was ______.
2. Traveling at a constant speed
3. Increasing its speed
4. Changing directions
5. Remaining at rest

1. According to the graph, between 4 and 10 seconds the ball was ______.
2. Traveling at a constant speed
3. Increasing its speed
4. Changing directions
5. Remaining at rest

1. According to the graph, between 12 and 14 seconds the ball was ______.
2. Traveling at a constant speed
3. Increasing its speed
4. Changing directions
5. Remaining at rest

1. According to the graph, between 16 and 18 seconds the ball was ______.
2. Traveling at a fast constant speed
3. Traveling at slow constant speed
4. Changing directions
5. Remaining at rest

1. According to the graph, between 18 and 20 seconds the ball was ______.
2. Traveling at a constant speed
3. Increasing its speed
4. Changing directions
5. Remaining at rest

1. According to the graph, between 20 and 24 seconds the ball was ______.
2. Traveling at a fast constant speed returning to start
3. Traveling at slow constant speed returning to start
4. Changing directions
5. Remaining at rest

1. According to the graph, between 26 and 28 seconds the ball was ______.
2. Traveling at a constant speed
3. Increasing its speed
4. Changing directions
5. Remaining at rest

Speed Equations

Solve the following problems using the speed triangle given.

1. It took Sally 5 hours to drive to her grandma’s house that was 400 miles away. If the speed limit was 85 mph, was she breaking the law? Why or why not?No, she is going 80 mph which is under the speed limit

1. How long will it take for a dragon to fly 50 miles traveling 40 miles/hour?0.8 hours or 48 minutes

1. If it took Pedro 250 seconds to walk across the entire mall at a rate of 2 meters/second, what is the length of the mall (distance)?500 meters