Answer:

Explanation:
The rotational kinetic energy when the cylinder is with the rope is:

where we used the fact that both rope and cylinder hast the same w. This E_k must conserve, that is, E_k must equal E_k when the rope leaves the cylinder. Hence, the final w is given by:
(1)
For Ic and Ir we can assume that the rope is a ring of the same radius of the cylinder. Then, we have:

Finally, by replacing in (1):

hope this helps!!
Answer:
Therefore it is save to carry a 62kg adult
Explanation:
From the question we are told that:
Mass 
Height of supporting Rock 
Length of Board
Mass of board 
Mass of adult
Generally the moment of balance about wedge part about is mathematically given by



where

therefore

if N=0 at fallen person

Therefore it is save to carry a 62kg adult
Answer:
B
Explanation:
did this yesterday with my friend
1. Ideal Mechanical Advantage (IMA): 9
Explanation:
For a wheel and axle system like the steering wheel, the IMA is given by:

where
is the radius of the wheel
is the radius of the axle
For the steering wheel of the problem, we see that
and
, so the IMA is

2. Efficiency: 88.9%
Explanation:
The efficiency of a system is defined as the ratio between the AMA (actual mechanical advantage) and the IMA:

In this problem, AMA=8 and IMA=9, so the efficiency is

When light is reflected by a mirror, the angle of incidence is always <span>A. equal to the angle of reflection. We know this by the Law of Reflection.</span>