High School

How much work (in kJ) must be done to stop a 1020 kg car traveling at 112 km/h?

(Note: Your answer should be negative.)

Answer :

Final answer:

The work done to stop the car is calculated by finding the initial kinetic energy of the car and subtracting the final kinetic energy, which is zero. The work done is equal to -1568.28 kJ.

Explanation:

To calculate the work done to stop the car, we need to find the initial kinetic energy of the car and subtract the final kinetic energy, which is zero since the car comes to a stop. The initial kinetic energy can be calculated using the formula:

Kinetic Energy = (1/2) * mass * velocity^2

Converting the speed from km/h to m/s, we get:

112 km/h = 31.1 m/s

Plugging in the values:

Kinetic Energy = (1/2) * 1020 kg * (31.1 m/s)^2

Calculating the work done:

Work = Initial Kinetic Energy - Final Kinetic Energy = (1/2) * 1020 kg * (31.1 m/s)^2 - 0

Simplifying the equation:

Work = 1568275.8 J = 1568.28 kJ (rounded to 2 decimal places)

Since we are asked for the work to be in kJ and negative, the correct answer would be:

-1568.28 kJ