During an experiment, a toy car accelerates forward for a total time of 5 s. Which of the following procedures could a student use to determine the average net force exerted on the car during the 5 s that the car accelerates?
A) Use a meterstick and stopwatch to measure the distance the car travels for the 5 s.
B) Use a balance to determine the mass of the car. Use a motion sensor to measure the speed of the car at a time of 0 s and a time of 5 s.
C) Use a balance to determine the mass of the car. Use a meterstick to measure the distance the car travels for the 5 s.
D) Use a motion sensor to measure the speed of the car at a time of 0 s and a time of 5 s. Use a meterstick to determine the distance the car travels for 5 s.
Question
Answer: B
Explanation: The motion sensor will measure the speed (velocity) of the car. Since the mass of the car has been measured, we can use formulas to calculate the average force.
Average net force = mass × acceleration
The mass of the toy car is measured first and noted
To calculate the velocity,
the car starts from rest since the velocity is associated with the distance and time after 5s.
Acceleration = velocity/time
With that the acceleration can be found.
acceleration is defined as change in velocity per unit time.
Then,
Force = mass × acceleration
Option B is the best answer