Answer:
13 N.
Step-by-step explanation:
The work done on an object is given by the formula:
Work = Force x Distance x cos(theta)
Where:
Force is the applied force
Distance is the distance the object is displaced
Theta is the angle between the applied force and the displacement
In this case, the car is pushed with a constant force of 13 N, and it gains 91 J of energy. We can use the formula for work to find the distance the car is displaced:
Work = Force x Distance x cos(theta)
91 J = 13 N x Distance x cos(0)
cos(0) = 1 (since the force is applied in the same direction as the displacement)
Distance = 91 J / (13 N x 1)
Distance = 7 m
Now that we know the distance, we can use the formula for work again to find the force:
Work = Force x Distance x cos(theta)
91 J = Force x 7 m x cos(0)
cos(0) = 1
Force = 91 J / (7 m x 1)
Force = 13 N
Therefore, the force used to push the car was 13 N.