Aman stands on a platform that is rotating (without friction) with an angular speed of 2.4 rev/s; his arms are outstretched and he holds a brick in each hand. the rotational inertia of the system consisting of the man, bricks, and platform about the central vertical axis of the platform is 6.2 kg · m2. by moving the bricks the man decreases the rotational inertia of the system to 2.0 kg · m2. (a) what is the resulting angular speed of the platform? rev/s

The resulting angular speed of the platform is 7.44 rev/s.

Explanation:

Given that,

Speed = 2.4 rev/s

Moment of inertia consist of the man  = 6.2 kg-m²

Moment of inertia by the bricks= 2.0 kg-m²

We need to calculate the resulting angular speed of the platform

Using law of conservation of momentum

Where,

= moment of inertia consist of  the man

= moment of inertia by the bricks

= angular speed of platform

Put the value into the formula

Hence, The resulting angular speed of the platform is 7.44 rev/s.

be subject to a force andchange its motion

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it