A car is strapped to a rocket (combined mass = 661 kg), and its kinetic energy is 66,120 J.

At this time, the rocket runs out of fuel and turns off, and the car deploys a parachute to slow down, and the parachute performs 36,733 J of work on the car.

What is the final speed of the car after this work is performed?

9.4 m/s

Explanation:

According to the work-energy theorem, the work done by external forces on a system is equal to the change in kinetic energy of the system.

Therefore we can write:

where in this case:

W = -36,733 J is the work done by the parachute (negative because it is opposite to the motion)

is the initial kinetic energy of the car

is the final kinetic energy

Solving,

The final kinetic energy of the car can be written as

where

m = 661 kg is its mass

v is its final speed

Solving for v,