What's the speed of a wave travelling at 500m/s with a wavelength of 25m

Ineed extreme for task 2. my student number is 571721. many to whoever solves this correctly, im in debt to you.

An object of dimensions 50 cm x 40 cm x 0.20 cm has a mass 60g. find its density in g/cm3 and kg/ m3

In all trials, the magnitude of the final velocity for g1 + g2 was less than the magnitude of any initial velocity. as mass increased, what happened to the velocity? the velocity decreased. the velocity increased. the velocity of g1 + g2 could not be measured. the velocity was not affected by the mass increase.