The kinetic energy of an object can be calculated using the formula:
Kinetic Energy (KE) = 0.5 * mass * velocity^2
Given: Mass of the car (m) = 1200 kg Initial velocity (u) = 30 m/s Final velocity (v) = 0 m/s (car comes to a stop)
Using the formula, we can calculate the initial kinetic energy and the final kinetic energy:
Initial Kinetic Energy (KEi) = 0.5 * m * u^2 Final Kinetic Energy (KEf) = 0.5 * m * v^2
Calculating the values:
KEi = 0.5 * 1200 kg * (30 m/s)^2 KEi = 0.5 * 1200 kg * 900 m^2/s^2 KEi = 540,000 Joules
KEf = 0.5 * 1200 kg * (0 m/s)^2 KEf = 0 Joules
Therefore, the initial kinetic energy of the car is 540,000 Joules, and the final kinetic energy when it comes to a stop is 0 Joules. The difference in kinetic energy represents the energy dissipated by the brakes as heat and other forms of energy.