The driver of a 1350 kg car, initially traveling at 10.6 m/s, applies the brakes, bringing the car to rest in a distance of 15.0 m.
Find the net work done on the car.
Not sure how to set this problem up.
work= change in KE= 1/2 m 10.6^2
There are harder ways.
find the acceleration: Vf^2=Vi^2+2ad solve for a
Then F=ma solve for force
work= force*distance.
To find the net work done on the car, we can use the work-energy principle, which states that the net work done on an object is equal to the change in its kinetic energy.
First, we need to calculate the initial and final kinetic energies of the car.
The initial kinetic energy (KE_initial) can be calculated using the formula:
KE_initial = 0.5 * mass * velocity^2
where mass is the mass of the car (1350 kg) and velocity is the initial velocity of the car (10.6 m/s).
Substituting the values, we get:
KE_initial = 0.5 * 1350 kg * (10.6 m/s)^2 = 0.5 * 1350 kg * 112.36 m^2/s^2 = 76122 J
Since the car comes to rest, its final kinetic energy (KE_final) is zero.
The net work done on the car can be calculated as the change in kinetic energy:
Net work done = KE_final - KE_initial
Substituting the values, we get:
Net work done = 0 - 76122 J = -76122 J
Therefore, the net work done on the car is -76122 Joules.
Note: The negative sign indicates that the work done is in the opposite direction of the displacement. In this case, the work done by the brakes opposes the motion of the car, resulting in negative work.