L1: Understanding Speed, Distance, and Time (7.7A)

Which formula correctly shows how to calculate the average speed of an object?

• Average Speed = Distance × Time

• Average Speed = Distance ÷ Time

• Average Speed = Time ÷ Distance

• Average Speed = Distance + Time

Answer explanation

The correct formula to calculate speed is Speed = Distance ÷ Time. This means speed is determined by dividing the total distance traveled by the time taken to travel that distance.

Tags

NGSS.MS-PS3-1

A cyclist travels 120 kilometers in 4 hours. What is the cyclist's average speed?

• 25 km/h

• 30 km/h

• 35 km/h

• 40 km/h

Answer explanation

To find the average speed, divide the total distance by the total time. Here, 150 km ÷ 3 hours = 50 km/h. Thus, the average speed of the car is 50 km/h.

According to TEKS 7.7A, which of the following best describes how to calculate the average speed of an object?

• The total distance traveled divided by the total time taken

• The fastest speed reached during a journey

• The speed at the start of a journey

• The speed at the end of a journey

Answer explanation

Average speed is defined as the total distance traveled divided by the total time taken. This formula provides a comprehensive measure of speed over the entire journey, unlike the other options which refer to specific moments.

A cyclist travels 24 kilometers in 2 hours. What is the cyclist's average speed in kilometers per hour?

• 10 km/h

• 12 km/h

• 15 km/h

• 20 km/h

Answer explanation

To find the average speed, divide the distance by time. The runner covers 10 km in 50 minutes. Convert 50 minutes to hours: 50/60 = 5/6 hours. Average speed = 10 km / (5/6 h) = 12 km/h, which is the correct answer.

According to TEKS 7.7A, which of the following best describes how to calculate average speed?

• Average speed is found by multiplying total distance and total time

• Average speed is found by adding total distance and total time

• Average speed is found by subtracting total time from total distance

• Average speed is found by dividing total distance by total time

Answer explanation

Speed is calculated as the ratio of total distance traveled to the total time taken. This means speed = distance/time, making the correct choice the ratio of total distance to total time.

A car travels 120 kilometers in 3 hours. What is the car's average speed?

• 30 km/h

• 40 km/h

• 50 km/h

• 60 km/h

Answer explanation

To find the average speed, divide the distance by the time. Here, 30 km ÷ 2 hours = 15 km/h. Thus, the cyclist's average speed is 15 km/h.

A car travels at a constant speed of 60 km/h. How far will it travel in 5 hours?

• 250 km

• 300 km

• 350 km

• 400 km

Answer explanation

To find the distance traveled, multiply speed by time: 80 km/h * 4 hours = 320 km. Therefore, the train travels 320 km.

Which of the following is the most appropriate unit to use when measuring the speed of a car traveling on a highway in the metric system?

• Meters per second (m/s)

• Kilometers per hour (km/h)

• Miles per hour (mph)

• Feet per second (ft/s)

Answer explanation

In the metric system, speed is commonly expressed in kilometers per hour (km/h), which is widely used for measuring vehicle speeds. Meters per second (m/s) is also a metric unit but less common for everyday speed.

Tags

NGSS.MS-PS3-1

A cyclist travels 120 kilometers in 3 hours. What is the cyclist's average speed?

• 30 km/h

• 35 km/h

• 40 km/h

• 45 km/h

Answer explanation

To find the average speed, divide the total distance by the total time. Here, 200 km ÷ 5 hours = 40 km/h. Thus, the average speed of the vehicle is 40 km/h.

Match the units to what they could be used to measure.

• Hours

• Time

• Feet per second

• Speed

• Meters

• Distance

Tags

NGSS.MS-PS3-1