Question

Calculate: Use the data from all three legs to solve for each triathlete’s average speed using the following information:

Leg 1: Swimming
a. Total distance: 5 km
b. Triathlete A’s total time: 1.0 h
c. Triathlete B’s total time: 2.0 h

Leg 2: Biking
a. Total distance: 45 km
b. Triathlete A’s total time: 3.0 h
c. Triathlete B’s total time: 2.5 h

Leg 3: Running
a. Total distance: 6 km
b. Triathlete A’s total time: 1.2 h
c. Triathlete B’s total time: 1.0 h

1a. Identify:
The (instantaneous/average) speed is the speed of the object at a given instant in time. The (instantaneous/average) speed is the speed of the object over a longer period of time.
Choose one:
a. Instantaneous
b. Average

1b. Apply Concepts:
The speedometer in a car gives the car’s ________________________ (instantaneous/average) speed.
Choose one:
a. Instantaneous
b. Average

Answer 1

1a. Choose one: b. Average

1b. Choose one: a. Instantaneous

Step-by-step explanation:

To calculate the average speed of an object, one must divide the total distance traveled by the total time it took to travel that distance. It is a way to describe the speed of an object over a longer period of time, instead of at a single moment.

For example:

Suppose a car travels 150 kilometers in 3.2 hours. Its average speed for the trip would be calculated using the formula:

Vavg = distance / time

Vavg = 150 km / 3.2 h

Vavg = 46.875 km/h

We would round this figure to the nearest whole number, so the car's average speed would be 47 km/h.

Answer to the Student's Question:

1a. The average speed is the speed of the object over a longer period of time.

1b. The speedometer in a car gives the car's instantaneous speed.

We apply this concept to calculate the average speed of the triathletes.

For Triathlete A, we sum the distances of all three legs and divide by the total time. Total distance = 5 km + 45 km + 6 km = 56 km. Total time = 1.0 h + 3.0 h + 1.2 h = 5.2 h. Average speed for Triathlete A = 56 km / 5.2 h = 10.77 km/h (rounded to two decimal places).

For Triathlete B, we do the same. Total distance = 5 km + 45 km + 6 km = 56 km. Total time = 2.0 h + 2.5 h + 1.0 h = 5.5 h. Average speed for Triathlete B = 56 km / 5.5 h = 10.18 km/h (rounded to two decimal places).