Calculating Braking Force of a Car
What was the braking force exerted on a car?
A car of mass 1200 kg traveling westward at 30 m/s is slowed to a stop in a time of 3 seconds by the car's brakes. What was the braking force?
a. 120 N
b. 12000 N
c. 15000 N
d. 150 N
Braking Force Calculation:
Final answer:
The braking force of the car is calculated using the formula for force which is mass times acceleration. Acceleration is found from the change in velocity divided by time. Substituting the given values, the absolute braking force is determined to be 12000 N.
Explanation:
To solve this question, we need to use the formula for force which is F = m*a. The mass of the car, m, is given as 1200 kg. The acceleration, a, can be found by using the formula for acceleration, which is the change in velocity divided by the change in time.
In this case, the initial velocity of the car is 30 m/s and it's slowed to a stop so the final velocity is 0 m/s. Thus, the change in velocity is -30 m/s. The change in time is 3 seconds.
Therefore, a = -30 m/s / 3 s = -10 m/s^2.
However, since force is a scalar quantity we are interested in the magnitude of the force exerted, therefore we only consider the absolute value.
Thus, the acceleration is 10 m/s^2.
By plugging the mass and acceleration into the formula for force, the braking force becomes F = 1200 kg * 10 m/s^2 = 12000 N.
So, the correct answer is b. 12000 N.