Home
Class 12
PHYSICS
A circular platform is mounted on a vert...

A circular platform is mounted on a vertical fritionless axle. Its radius is r=2m and its moment of inertia is l=200 `kg-m^(2)`. It is initially at rest. A 70 kg man stands on the edge of the platform and begins to walk along the edge at speed `v_(0)=1.0 m//s,` relative to the ground. The angular velocity of the platform is

A

`(3pi)/(2)s`

B

`2pis`

C

`(pi)/(2)s`

D

`pis`

Text Solution

Verified by Experts

The correct Answer is:
B
`I_(1)omega_(1)+I_(2)omega_(2)=0`
`200((1)/(2))+200omega_(2)=0`
`omega_(2)=-(1)/(2)`
`omega_(R)=omega_(1)-omega_(2)=1"rad/sec"`
`T=(2pi)/(omega)=2pisec`
Promotional Banner

Similar Questions

Explore conceptually related problems

A circular platform is mounted on a vertical frictionless axle. Its radius is r = 2 m and its moment of inertia I = 200 kg m^2 . It is initially at rest. A 70 kg man stands on the edge of the platform and begins to walk along the edge at speed v_0 = 1 m s^-1 relative to the ground. The angular velocity of the platform is: a) 1.2 rad/s b) 0.4 rad/s c) 0.7 rad/s d) 2 rad/s

A circular platform is mounted on a frictionless vertical axle. Its radius R = 2m and its moment of inertia about the axle is 200 kg m^(2) . It is initially at rest. A 50 kg man stands on the edge at the platform and begins to walk along the edge at the speed of 1ms^(-1) relative to the ground. Time taken by the man to complete one revolution is :

The rotational kinetic energy of a disc is 450 J and its moment of inertia is 100 kg m^2 . What is its angular momentum ?

A man of mass 100 kg stands at the rim of a turtable of radius 2 m and moment of inertia 4000 kgm^(2) mounted on a vertical frictionless shaft at its centre. The whole system is initially at rest. The man now walks along the outer edge of the turntable with a velocity of 1m//s relative to the earth a. With what angular velocity and in what direction does the turntable rotate? b. Through what angle will it have rotated when the man reaches his initial position on the turntable? c. Through what angle will it have rotated when the man reaches his initial position relative to the earth?

A solid cylinder of mass 20kg has length 1 m and radius 0.2 m. Then its moment of inertia (in kg- m^(2) ) about its geometrical axis is :

A wheel of mass 8 kg has moment of inertia equals to 0.5 "kg-m"^(2) . Determine its radius of gyration.

A circular platform is free to rotate in a horizontal plane about a vertical axis passing through its centre. A tortoise is sitting at the edge of the platform. Now the platform is given an angular velocity omega_(0) . When the tortoise move along a chord of the platform with a constant velocity (with respect to the platform),

A man of mass m stands on a horizontal platform in the shape of a disc of mass m and radius R , pivoted on a vertical axis thorugh its centre about which it can freely rotate. The man starts to move aroung the centre of the disc in a circle of radius r with a velocity v relative to the disc. Calculate the angular velocity of the disc.

A child with mass m is standing at the edge of a merry go round having moment of inertia I , radius R and initial angular velocity omega as shown in the figure. The child jumps off the edge of the merry go round with tangential velocity v with respect to the ground. The new angular velocity of the merry go round is

A man of mass m is standing on a platform of mass M kept on smooth ice. If the man starts moving on the platform with a speed v relative to the platform with what velocity relative to the ice does the platform recoil?