Which trigonometric functions are equivalent to cos ø?

Alead ball is dropped into a lake from a diving board 5m above the water . it hits the water with a certain velocity and then sink with constant velocity in bottom . it reaches the bottom 5 second after it is dropped if g= 10m/s2 . find depth of the lake and average velocity of the ball ?

In the first law of thermodynamics, triangle e=q-w, what does q stand for

Atomic nuclei of almost all elements consist of