A particle is kept fixed on a turntable rotating uniformly. As seen from the ground the particle goes in a circle, its speed is 20 cm/s and acceleration is 20 cm/s2. The particle is now shifted to a new position to make the radius half of the original value. The new values of the speed and acceleration will be
Velocity of a particle in a circular motion is equal to 
, so, if 
is constant the velocity is proportional to the radius. So, in this case the particle is kept at half the radius so velocity will be halved = 10cm/sec. In the same way, acceleration is equal to 
, where 
is constant, thus, acceleration is also proportional to r. therefor the acceleration is 10cm/sec2.
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