# Physics question involving tangential acceleration, tangential velocity and centripetal acceleration?

I am really going nuts trying to figure out how to do this physics question... I'll reward best answer points to whomever will not only get the answers but explain to me how and why they got them...

(a)What is the tangential acceleration of a bug on the rim of a 10-in. diameter disk if the disk moves from rest to an angular speed of 78 rev/min in 3.0s.? (b) When the disk is at its final speed, what is the tangential velocity of the bug? (c) One second after the bug starts from rest, what are its tangential acceleration, centripetal acceleration and total acceleration?

### 1 Answer

- 1 decade agoBest answer
Final velocity v = 2*pi*r*w, where w is the angular speed in rpm

=> v = (78/60) * 2 * pi * (5 * 2.5) / 100 metres/s

Use v = u + at to get the tangential acceleration.

(78/60) * 2 * pi * (5 * 2.5) / 100 = 0 + a*3

Get tangential acceleration

Centripetal accel = v^2/r. Calculate it.

And tangental accel and centripetal accel form a right triangle. Use pythagoras theorem to find the net accel as sqrt( centripetal accel^2 + tangential accel^2)