Using the theorem of kinetic energy
1/2mVf² - 1/2mVi²= WF + Wp, Wp=0
WF = F. AB, AB=5m and F= 40N, m=20kg
so the final kinetic is KEf= 1/2mVf² = WF =<span>F. AB= 40*5=200J
</span>
the final velocity is 1/2mVf² <span>=200, implies Vf= sqrt(20)=2sqrt(5)m/s</span>
Answer:
W = 750 [J]
Explanation:
The question should be related to work, work in physics is defined as the product of force by distance. In this way, we can use the following equation.

where:
F = force = 30 [N]
d = distance = 25 [m]
W = work [J]
Now replacing:
![W=30*25\\W=750 [J]](https://tex.z-dn.net/?f=W%3D30%2A25%5C%5CW%3D750%20%5BJ%5D)
I. the type of wave ... electromagnetic or mechanical
(II. amplitude doesn't influence the speed of any wave)
III. the medium in which the wave travels ... completely determines the wave speed