Question

The beam of light house makes one complete revolution every 20 seconds how many degrees is it rotate in five seconds

Answer 1

Answer:

Every 5 seconds the beam rotates 90 degrees;

$90^{\circ}$

Explanation:

Given that the beam of a lighthouse makes one complete revolution every 20 seconds.

one complete revolution is;

$360^{\circ^{}}$

The rate of rotation is;

$r=\frac{360^{\circ}}{20}=18^{\circ}\text{ per second}$

The number of degrees it will rotate in 5 seconds is;

$\begin{gathered} x=5\times r=5\times18^{\circ}per\text{ second} \\ x=90^{\circ} \end{gathered}$

Therefore, every 5 seconds the beam rotates 90 degrees;

$90^{\circ}$