Answer:
1369.5 J
Explanation:
According to the work-energy theorem, the work done on an object is equal to the change in kinetic energy of the object itself.
Therefore, we can write:
[tex]W=K_f-K_i=\frac{1}{2}mv^2-\frac{1}{2}mu^2[/tex]
where:
W is the work done on the hovercraft
m = 83.0 kg is the mass of the hovercraft
u = 4.0 m/s is the initial velocity (in the positive x-direction)
v = 7.0 m/s is the final velocity (in the positive y-direction)
Here the direction of motion of the hovercraft has changed; however, we can ignore this fact, since work is a scalar so the direction of the velocity does not matter.
Therefore, the work done by the force is:
[tex]W=\frac{1}{2}(83.0)(7.0)^2-\frac{1}{2}(83.0)(4.0)^2=1369.5 J[/tex]
