Match the wave motion with the correct seismic wave.

P wave
S wave
Surface wave

A. motion that involves compression and expansion of the material through which it passes; may pass through solids, liquids, and gases

B. motion that involves oscillation perpendicular to the direction of propagation; only passes through solids

C. motion at Earth's surface that may move materials side to side, or up and down

If the helicopter is not moving, then it is not being accelerated.

By second Newton's law we have that:

F = m*a

Force equals mass times acceleration.

Then if we do not have acceleration, we have:

F = m*a = m*0 = 0.

Then the total force must be zero.

So if the gravitational force (pulling down) is 115N, then the force of the propeller must be such that:

Total force = F - 115N = 0

F = 115N

The force of the propeller must be also of 115N, but in the opposite direction.