How much work must be done to stop a 1200 kg car traveling at 135 km/h?
The work that must be done by the car equals the initial kinetic energy.
To determine the amount of work required to stop the car, we need to consider the principle of work and energy. Work done on an object is equal to the change in its kinetic energy.
First, we need to convert the initial velocity of the car from km/h to m/s. Since 1 km/h is equal to 0.2778 m/s, the initial velocity is 135 km/h * 0.2778 m/s = 37.5 m/s.
The final velocity is 0 m/s, as the car needs to come to a complete stop.
The initial kinetic energy (KE) of the car can be calculated using the equation KE = (1/2) * mass * velocity^2. Plugging in the values, we have KE = (1/2) * 1200 kg * (37.5 m/s)^2 = 843,750 J.
Since the final velocity is 0 m/s, the final kinetic energy is also 0 J.
The work done to stop the car is then equal to the change in kinetic energy, which is given by the equation Work = final KE - initial KE.
Therefore, the work required to stop the car is 0 J - 843,750 J = -843,750 J.
It is important to note that the negative sign indicates that work is done against the motion of the car (in the opposite direction), which slows it down and eventually brings it to a stop.