Answer:
Friction force is 0.1375 N
Solution:
As per the question:
Radius of the metal disc, R = 4.0 cm = 0.04 m
Magnetic field, B = 1.25 T
Current, I = 5.5 A
Force on a current carrying conductor in a magnetic field is given by considering it on a differential element:

Integrating the above eqn:

(1)
Now the torque is given by:
(2)
From eqn (1) and (2):

Thus the Frictional force is given by:

The kinetic energy of the block when it reaches the bottom is 39.2 J.
<h3>
Kinetic energy of the block at the bottom</h3>
Apply the principle of conservation of energy.
K.E(bottom) = P.E(top)
P.E(top) = mgh
where;
- m is mass of the block
- g is acceleration due to gravity
- h is the vertical height of fall
P.E(top) = 5 x 9.8 x 0.8
P.E(top) = K.E(bottom) = 39.2 J
Learn more about kinetic energy here: brainly.com/question/25959744
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This question can be solved by using Pythagora's Theorem.
The resultant magnitude of the movement is "42.5 units".
The x and y components of the movement are given. We can use Pythagora's Theorem to find the resultant of these movements. Hence, applying the Pythagora's Theorem<em>:</em>

where,
d = resultant movement = ?
= movement in x direction = 32 units
= movement in y direction = 28 units
Therefore,

<u>d = 42.5 units</u>
Learn more about Pythagora's Theorem here:
brainly.com/question/343682?referrer=searchResults
The attached picture shows Pythagora's Theorem<em>.</em>