Q.79

Expert-verified
Found in: Page 334

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# A 200 g, 40-cm-diameter turntable rotates on frictionless bearings at 60 rpm. A 20 g block sits at the center of the turntable. A compressed spring shoots the block radially outward along a frictionless groove in the surface of the turntable. What is the turntable’s rotation angular velocity when the block reaches the outer edge?

The turntable’s angular velocity is 5.76 rad / sec

See the step by step solution

## Step1: Given information

mass of turn table = 200 gm = 0.2 kg

Diameter of turntable = 40 cm = 0.4 m

so radius of turn table =0.2 m

mass of block = 20 gm =0.02 kg

rpm = 60.

## Step2: Explanation

Use the law of conservation for momentum

initial momentum = final momentum

Li= Lf ..............................................(1)

Get initial momentum

Li= Ii ωi.............................................(2)

Find moment of inertia

Substitute this in equation(2)

Substitute the given value

Now find the final momentum

Substitute the given values

Equate (4) and (6) we get