Unit 2 Grade 7: Relationships Between Forces and Motion (ALL)

A jet airliner flies 4,100 km from New York City to San Francisco in 4.25 h. What is its average speed?

• 964.7 km/h

• 850.0 km/h

• 1025.0 km/h

• 900.0 km/h

To determine their average pitching speed, a student throws a tennis ball against a wall that is 2.0 m away. Their partner records the time it takes for the tennis ball to hit the wall. Their data are shown in Table 1.

What is the student’s average pitching speed in meters per second?

• 10 m/s

• 8 m/s

• 12 m/s

• 6 m/s

Which has the greatest average speed?

• a. a boat sailing 80 km in 2 hours

• b. a car driving 90 km in 3 hours

• c. a train traveling 120 km in 3 hours

• d. a truck moving at 50 km for 1 hour

A model train moves 18.3 m in 122 s. What is the train’s average speed?

• 6.67 m/s

• 0.18 m/s

• 0.15 m/s

• 7 m/s

The library is 1.0 km from a student's house. It takes 0.4 h to walk to the library and then back home. What is the student's average velocity in kilometers per hour (km/h)?

• 0 km/h

• 0.2 km/h

• 2.5 km/h

• 5 km/h

Which pair have the same velocity?

• a. a boy walking east at 2km/h and a man walking east at 4km/h

• b. a car standing still and a truck driving in a circle at 4km/h

• c. a dog walking west at 3km/h and a cat walking west at 3km/h

• d. a girl walking west at 3km/h and a boy walking south at 3km/h

Race cars travel around the racetrack shown in the diagram at a constant speed of 45m/s. Which statement correctly describes what happens to a race car's velocity as it travels from point A to point B?

• The velocity is constant because the speed is constant.

• The velocity changes because the car changes direction.

• The velocity is constant because the distance and displacement are the same.

• The velocity changes because the distance and displacement are the same.

Which statement correctly describes the distance-time graph for the sea turtle?

• The line would curve upward and to the right.

• The line would go up and down

• The line would be straight, moving upward to the right.

• The line would point upward and then downward.

Tags

NGSS.MS-PS3-1

The distance-time graph shows the motion of an elevator. Which statement best describes the motion of the elevator?

• The elevator traveled down between 1 and 2 minutes.

• The elevator stayed still between 1 and 2 minutes.

• The elevator traveled up between 2 and 3 minutes.

• The elevator stayed still between 2 and 3 minutes.

Observe the photo. The driver of a car accidentally leaves his briefcase on top of the car and prepares to leave for work. Because the car accelerated slowly, the briefcase did not move initially and is now moving with the car. According to Newton's first law of motion, what will happen if the car comes to a sudden stop?

• The briefcase will continue moving forward and slide off the front of the car.

• The briefcase will remain in place because the forces acting upon it are balanced.

• Friction will keep the briefcase in place, even while the car comes to a stop.

• It is impossible to predict what will happen without knowing the mass of the briefcase.