An electric drill starts from rest and rotates with a constant angular acceleration. After the drill has rotated through a certain angle, the magnitude of the centripetal acceleration of a point on the drill is 7.9 times the magnitude of the tangential acceleration. What is the angle

The angle is 3.95 rad.

Explanation:

The angle can be calculated as follows:

Where:

: is the final angular speed

ω₀: is the initial angular speed = 0 (it starts from rest)

α: is the angular acceleration

θ: is the angle=?

The centripetal acceleration is:

And the tangential acceleration is:

Since the magnitude of the centripetal acceleration is 7.9 times the magnitude of the tangential acceleration:

Now, the angle is:

Therefore, the angle is 3.95 rad.

I hope it helps you!          

no. dot product   =0 when vecs at right angles