Answer:
So the acceleration of the child will be 
Explanation:
We have given angular speed of the child 
Radius r = 4.65 m
Angular acceleration 
We know that linear velocity is given by 
We know that radial acceleration is given by 
Tangential acceleration is given by

So total acceleration will be 
Answer:
The intensity I₂ of the light beam emerging from the second polarizer is zero.
Explanation:
Given:
Intensity of first polarizer = Io/2
For the second polarizer, the intensity is equal:

Answer:
b
Explanation:
he keep the thermoter in the water longer
Answer:

Explanation:
Torque is defined as the cross product between the position vector ( the lever arm vector connecting the origin to the point of force application) and the force vector.

Due to the definition of cross product, the magnitude of the torque is given by:

Where
is the angle between the force and lever arm vectors. So, the length of the lever arm (r) is minimun when
is equal to one, solving for r:

Answer:
option C
Explanation:
given,
energy dissipated by the system to the surrounding = 12 J
Work done on the system = 28 J
change in internal energy of the system
Δ U = Q - W
system losses energy = - 12 J
work done = -28 J
Δ U = Q - W
Δ U = -12 -(-28)
Δ U = 16 J
hence, the correct answer is option C