Question

A 2.3 kg , 20-cm-diameter turntable rotates at 100 rpm on frictionless bearings. Two 500 g blocks fall from above, hit the turntable simultaneously at opposite ends of a diagonal, and stick. What is the turntable's angular velocity, inrpm, just after this event?

Answer 1

Answer

ω2=82.1 rpm

Explanation:

given                                    required              

m1=2.3 kg                           ω2=?              

m2+m3=0.5kg

r1=10 cm

ω1=100 rpm

solution

Using the application of conservation of angular momentum we can solve as follows/

L before collision= L after collision

m1r²ω1=(m1+m2+m3)r²ω2

2.3 kg×0.1² m²×100 rpm=(2.3 kg+0.5 kg)×0.1²m²×ω2

2.3 rpm=0.028×ω2

ω2=82.1 rpm