One second is equal to

The number of beats produced per second is equal to the –

A plane is going in circles around an airport. The plane takes 3 minutes to complete one round. The angle of elevation of the plane from a point P on the ground at time t seconds is equal to that at time (t + 30) seconds. At time (t + x) seconds, the plane mes vertically above the point P. What is x equal to ?

The product (ampere xx second ) is equal to the number of :