Answer:
D
Explanation:
From the information given:
The angular speed for the block 
Disk radius (r) = 0.2 m
The block Initial velocity is:

Change in the block's angular speed is:

However, on the disk, moment of inertIa is:

The time t = 10s
∴
Frictional torques by the wall on the disk is:

Finally, the frictional force is calculated as:


E, 63% of the value. I forget the rationale behind it but I learnt that in engineering. 90% confident for that answer.
Answer:
300 Pascal
Explanation:
Given
weight or force (F) = 6000 N
area (A) = 20 m²
pressure (p) = ?
we know
the force acting normally per unit area is pressure. So
P = F / A
= 6000 / 20
= 300 Pascal
Hope it will help :)