This is a suggested answer to the GCE O Level Pure Physics examination, year 2019, Paper 1, multiple choice question 8.
The question provided the following data on a car that is accelerating
- Mass of car is 800kg
- The car’s engine exerts a driving force of 2500N
- Acceleration of car is 2.0m/s2
The student is required to calculate the resistive force acting on the car.
The answer is A. That is, the resistive force is 900N.
The Resultant force that resulted in the car accelerating is given by the formula:
Resultant Force, F = Mass x acceleration
F = 800kg x 2.0m/s2
The Resultant force is actually the result of the force the car engine exerts (which is given as 2500N) and the resistive force.
Hence, the Resistive Force = 2500N-1600N