Answer:
The magnitude of induced emf is 5.4 V
Explanation:
Given:
Magnetic field
T
Area of loop

Time take to reduce loop to zero
sec
To find induced emf we use faraday's law,
Induced emf is given by,

Here minus sign shows lenz law, for finding magnitude of emf we ignore it.
Where
Put the value of flux and find induced emf,


V
Therefore, the magnitude of induced emf is 5.4 V
consider the motion of the ball in vertical direction after it rolls off the table
v₀ = initial velocity of the ball in vertical direction = 0 m/s
a = acceleration = acceleration due to gravity = 9.8 m/s²
Y = vertical displacement = height of the table = 0.91 m
t = time spent in air by the ball
Using the kinematics equation
Y = v₀ t + (0.5) a t²
0.91 = 0 t + (0.5) (9.8) t²
t = 0.43 sec
v = final velocity in vertical direction just before it hits the ground
Using the kinematics equation
v = v₀ + at
v = 0 + (9.8) (0.43)
v = 4.21 m/s
KE=1/2mass time velocity squared so 15kg x 20^2=6000