Which do you need to calculate the speed of a wave?

To calculate the speed of a wave you need its frequency ( Hz) and wavelength
(m)

Once you have it slot in into this equation c = f *  λ
where c =speed of the wave
            f = frequency
             λ = wavelength

Hope this helps :).

Speed, v = fλ

where f = frequency in Hz, and λ = wavelength in m.

Hence to calculate the speed, you need to the know the value of the frequency and wavelength of the wave.

Magma  is composed of molten rock and is  stored  in the earth's crust. lava is  magma  that reaches the surface of our planet through a volcano vent.

W= fd
where f is an applied force and d is the distance over which it is applied. when a parachuting skydiver is at constant velocity, he is experiencing "terminal velocity", the point at which his acceleration down is canceled out by air resistance. that means that the resisting force of the air is equal to his weight, but in the opposite direction. with this, we can solve for the work done by the force.
w = fd
w = (92.0)(9.81 m/s^2) (325)
w= 2.93 x 10^5 j
the value for work in this case is positive because it is pushing up on the skydiver, who has a downward force of gravity.
therefore the answer is 2.93 x 10^5 j