HETAV PATEL

Grade 11,

Two identical circular discs A and B each of mass m and radius R are placed horizontally on a smooth horizontal surface with their centres fixed to the surface and touching each other. An impulse P° is applied to disc A. If there is no slipping between the discs, the angular velocity of each discs will be?

Two identical circular discs A and B each of mass m and radius R are placed horizontally on a smooth horizontal surface with their centres fixed to the surface and touching each other. An impulse P° is applied to disc A. If there is no slipping between the discs, the angular velocity of each discs will be?

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Grade:12th pass

2 Answers

Vidhi Bhati
11 Points
6 years ago
Angular Impulse = Change in momentumAnd here Momentum is conserved. So here.. P°=mv Where v is the liner velocity.As per pure rolling concept.. v=wR So, P°=mwR Or w=P°/mrAnd each disc will obviously have the same magnitude of angular velocity, only the sense of Rotation will be different.
Ashima Tripathi
34 Points
6 years ago
If there is friction between the two discs then-For disc 1: P°×r - f×r=lwFor disc 2: f×r= lw On solving these two equations with I = (mr^2)÷2,we get w=P°/mrHere, I assumed that due to the impulse imparted disc 1 starts rotating in anti clockwise direction, so disc 2 which is at left to disc 1 , applies friction on disc 1 in +k^ ( taking disc to be in x-z plane) . As a result disc 1 also applies the same frictional force on disc 2 in -k^ .If there is no friction then -Disc 2 will not rotate as there is no torque.For disc 1: P°×r=Iww=2P°/mr

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