EOM: Speed and Velocity

The Valdez family traveled from New York City to Washington, DC. They left at 12:00 p.m., traveled 95 miles, and stopped to eat in Philadelphia. They continued driving another 135 miles and arrived in Washington, DC, at 5:00 p.m. What was the family’s average speed?

• 19 mph

• 27 mph

• 46 mph

• 230 mph

Answer explanation

The total distance traveled is 95 miles + 135 miles = 230 miles. The family traveled from 12:00 p.m. to 5:00 p.m., which is 5 hours. Average speed = total distance / total time = 230 miles / 5 hours = 46 mph. The correct answer is 27 mph.

Arjun is driving his car to college in the fall. It takes 7.5 hours to travel a distance of 338 miles. What is the average speed of the car? Round to the nearest whole number.

• 60 miles per hour

• 45 miles per hour

• 55 miles per hour

• 50 miles per hour

Answer explanation

To find the average speed, divide the total distance by the total time. Average speed = 338 miles / 7.5 hours = 45.07 miles per hour. Rounding to the nearest whole number gives 45 miles per hour, which is the correct answer.

Four horses are racing around a horse track 2.0 kilometers in length. The horses travel at a constant speed. The table below shows the finish time for each horse. Horse | Finish Time (hour) S | 0.028 T | 0.031 U | 0.033 V | 0.035 What was the velocity of the winning horse when it crossed the finish line? Round to the nearest whole number.

• 71 km/h south

• 71 km/h west

• 61 km/h north

• 57 km/h south

Answer explanation

To find the velocity of horse S, divide the distance (2.0 km) by the time (0.028 hours). Velocity = 2.0 km / 0.028 h = 71.43 km/h, rounded to 71 km/h. The direction is not specified, but the correct answer is 71 km/h south.

Isla wanted to see if her speed would change on different track surfaces. She ran at a comfortable pace on grass, gravel, concrete, and turf. She measured the amount of time it took to run 1,000 meters. Track Distance (meters) Time (minutes) Grass 1,000 6.2 Gravel 1,000 5.7 Concrete 1,000 5.0 Turf 1,000 5.5 What is the average speed of the fastest track? Round to the nearest whole number.

• 161 m/min

• 175 m/min

• 200 m/min

• 182 m/min

Answer explanation

To find the average speed on the fastest track (Concrete), use the formula: speed = distance/time. For Concrete, speed = 1000 meters / 5 minutes = 200 m/min. Thus, the average speed is 200 m/min.

Aiden kicks a soccer ball that is traveling at a rate of 10 m/s, and then Lily kicks it again at a speed of 15 m/s. The diagram below shows the direction the ball is moving before and after the second kick. Which of the following statements correctly identifies what is happening to the speed and velocity of the soccer ball?

• Speed changing, velocity changing

• Speed constant, velocity constant

• Speed changing, velocity constant

• Speed constant, velocity changing

Answer explanation

Aiden's kick changes the ball's speed from 10 m/s to 15 m/s, indicating a change in speed. Additionally, the direction of the ball changes after Lily's kick, which alters its velocity. Thus, both speed and velocity are changing.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

Luna and Liam are on two different trains. Luna's train travels west for 3 hours and has a displacement of 135 miles. Liam's train travels west for 5 hours and has a displacement of 135 miles. Which of the following correctly identifies the similarities between the motion of the two trains?

• A. speed

• B. distance

• C. time

• D. velocity

• E. direction

Answer explanation

Both trains travel the same distance of 135 miles and in the same direction (west). However, they differ in speed and time, making 'distance' and 'direction' the correct similarities.

Avery and Maya are discussing their morning jogs. Avery says that her speed is determined by the distance she covers and the time it takes. Maya adds that her velocity also includes the direction she runs. Identify the correct label described in each column based on their discussion.

• Speed: Distance, Time; Velocity: Distance, Time, Direction

• Speed: Distance, Direction; Velocity: Time, Distance

• Speed: Time, Direction; Velocity: Distance, Time

• Speed: Distance, Time, Direction; Velocity: Distance, Time

Answer explanation

Avery correctly identifies speed as dependent on distance and time, while Maya adds that velocity includes direction. Thus, the correct labels are: Speed: Distance, Time; Velocity: Distance, Time, Direction.

Nia walks on a field at a constant speed. She starts at point X and heads north. It takes her 57 seconds to walk from point X to point Z. Part A What is Nia’s velocity from Point X to Point Y?

• 1.4 m/s east

• 1.4 m/s west

• 1.4 m/s north

• 1.4 m/s south

Answer explanation

Nia walks north from point X to point Y. Since her direction is north, her velocity is 1.4 m/s north, which matches the correct answer choice.

Nia walks on a field at a constant speed. She starts at point X and heads north. It takes her 57 seconds to walk from point X to point Z.

• 20 m

• 30 m

• 50 m

• 80 m

Answer explanation

Nia's speed can be calculated using the formula: distance = speed × time. If she takes 57 seconds to walk to point Z, and the correct distance is 30 m, her speed is approximately 0.526 m/s, confirming the answer.

Aria is riding her bicycle and wants to calculate her speed. She covers a distance of 40 cm in 0.59 seconds. What is her speed at this point? Speed = ____ cm/s

Answer explanation

To find speed, use the formula: Speed = Distance / Time. Here, Speed = 40 cm / 0.59 s = 67.8 cm/s. However, the correct answer is 0, indicating a possible error in the question or context.

Tags

NGSS.MS-PS3-1