Physics Motion Quiz 04

The table shows the position versus time of a dog chasing a frisbee thrown by its person. How far did the dog run? (The position is measured from the person.)

• 3 meters

• 4 meters

• 8 meters

• 11 meters

• 19 meters

Answer explanation

The dog ran from the person's position to the frisbee. The final position of the dog is 11 meters from the person, indicating that the dog ran a total distance of 11 meters.

The skier in the diagram shown is at position A when t = 0 minutes, at position B when t = 1 minute, at position C when t = 2 minutes, and at position D when t = 3 minutes. Assume right is positive and left is negative. What is the distance in meters? (Write the number without units.)

Answer explanation

The skier starts at position A and returns to the same position after moving to B, C, and D. Since the starting and ending positions are the same, the total distance traveled is 0 meters.

The skier in the diagram shown is at position A when t = 0 minutes, at position B when t = 1 minute, at position C when t = 2 minutes, and at position D when t = 3 minutes. Assume right is positive and left is negative. What is the displacement in meters? (Write the number without units.)

Answer explanation

The skier starts at position A and ends at position D, which are the same point. Therefore, the displacement, defined as the change in position, is 0 meters.

You are going to Grandma’s house, which is 20 miles due north of you. Then you go to Safeway, which is 10 miles directly east of Grandma’s house. You then travel 20 miles due south to your workplace. What is your displacement?

• 10 miles, East

• 10 miles, West

• 20 miles, East

• 20 miles, West

Answer explanation

Starting at your location, you go 20 miles north to Grandma's, then 10 miles east to Safeway, and finally 20 miles south to your workplace. Your final position is 10 miles east of your starting point, resulting in a displacement of 10 miles, East.

A radio-controlled car travels in one direction down a straight track. A part of the motion is shown in the top view diagram shown. Every second the car sprays a paint dot on the track to mark its position. Which description best fits the motion of the car from t = 4 seconds to t = 6 seconds?

• Slows down and stops because the dots stop.

• Slowing down because the postion/time ratio is getting smaller.

• Moving at a constant speed because the dots are equally spaced.

• Moving fast because the position readings are very high

Answer explanation

The correct choice is 'Moving at a constant speed because the dots are equally spaced.' This indicates that the car maintains a steady speed, as equal spacing of paint dots shows consistent distance covered over equal time intervals.

Tags

NGSS.MS-PS3-1

Some students decide to take a bike ride. For the first two hours they travel at a speed of 15 mi/hr, they then stop for lunch for an hour. The students then ride for another hour at 10 mi/hr. What was their average speed for the entire trip?

• 10 mi/hr

• 12.5 mi/hr

• 13.3 mi/hr

• 15 mi/hr

Answer explanation

The total distance is (15 mi/hr * 2 hr) + (10 mi/hr * 1 hr) = 30 mi + 10 mi = 40 mi. The total time is 2 hr + 1 hr + 1 hr = 4 hr. Average speed = total distance / total time = 40 mi / 4 hr = 10 mi/hr.

Sheila runs the 200-meter race for her track team. She runs the first 100 meters at 9.00 meters per second. She runs the final 100 meters at 10.0 meters per second. How long did it take Sheila to run the first 100 meters?

• 9.0 s

• 10.0 s

• 11.1 s

• 20.0 s

Answer explanation

To find the time for the first 100 meters, use the formula time = distance / speed. For the first 100 meters at 9.00 m/s, time = 100 m / 9.00 m/s = 11.1 s. Thus, the correct answer is 11.1 s.

Patti runs the 200-meter race for her track team. She runs the first 100 meters at 9.0 meters per second. She runs the final 100 meters at 10 meters per second. What was Patti’s average speed for the entire race?

• 9.48 m/s

• 10.0 m/s

• 11.1 m/s

• 21.1 m/s

Answer explanation

Patti runs 100 meters at 9.0 m/s (11.11 seconds) and 100 meters at 10.0 m/s (10 seconds). Total time = 11.11 + 10 = 21.11 seconds. Average speed = total distance / total time = 200 m / 21.11 s = 9.48 m/s.

A beetle walks along a road. The graph of its motion is shown. What was its average speed in centimeters per second for the entire trip? (Write the number without units.)

Answer explanation

To find the average speed, divide the total distance by the total time. If the graph shows no net movement (starting and ending at the same point), the total distance is zero, resulting in an average speed of 0 cm/s.

Tags

NGSS.MS-PS3-1

A beetle walks along a road. The graph of its motion is shown. What was its average velocity in centimeters per second for the entire trip? (Write the number without units.)

Answer explanation

The average velocity is calculated as total displacement divided by total time. If the beetle returns to its starting point, the total displacement is zero, resulting in an average velocity of 0 cm/s.

Tags

NGSS.MS-PS3-1