Is the following relation a function?

Jonathan puts $400 in a bank account. each year the account earns 6% simple interest. how much interest will be earned in 5 years?

The motion of a weight that hangs from a spring is represented by the equation h=8sin(2pi/3t). it models the weight’s height above or below the rest position as a function of time. approximately when will the object be 3 inches above the rest position?

Acabbage palmetto has a height of 80 feet.what is the approximate height of the tree in meters