The head of an industrial machine moves in a straight line horizontally backwards and forwards from a central position. The movement can be modelled using the sine wave d = 80 sin ( pie t), where d is the horizontal distance (in cm) from the central starting position, and t is the time after the machine starts running (in second).

Question

choose the 2 correct statements about the motion of the machine:
a) the maximum distance that the machine head moves horizontally from its central starting position is 80cm
b) the maximum distance that the machine head moves horizontally from its central starting position is 40 cm
c) the machine head will make 50 complete cycles in a minute
d) the machine head will make 30 complete cycles in a minute
e) the machine head will make one complete cycle in half a minute
f) the machine head will make one complete cycle in 2 minutes.

I'm assuming its A and E. Anybody have a better idea if I'm wrong?