Answer:
Work done is 882000joule.
power is 29400watt.
Explanation:
given,
Mass(m)=500kg
Acceleration due to gravity(g)=9.8m/s²
Height(h)=6m
Time taken(t)=30s
Workdone=?
Power=?
now,
workdone=force*displaxement
= m*g*h
=500*9.8*6
=8,82,000joule
so, the work done by the man is 8,82,000joule.
then,
power=workdone/time taken
=8,82,000/30
=29,400watt
so, the required power to lift a load is 29,400watt.
When light moves from a medium with higher refractive index to a medium with lower refractive index, the critical angle is the angle above which there is no refracted ray, and it is given by:

(2)
where

is the refractive index of the second medium and

is the refractive index of the first medium.
We can find the ratio

by using Snell's law:

(1)
where

is the angle of incidence

is the angle of refraction
By using the data of the problem and re-arranging (1), we find

and if we use eq.(2) we can now find the value of the critical angle:
Answer:
It will be easier to break the meter rule with the long side against my knee.
Explanation:
To break the meter rule involves the principle of bending moment. The long side will require less force to generate the same amount of bending moment that will have to be generated to break the meter rule. The short side on the other hand will require more force to generate this mount of bending moment. This is because the shorter has a very small surface area, which concentrates the force on your knee. The pressure is then dissipated as more pressure to your knee. Th longer side has a lesser surface area so, most of the force is used in breaking the meter rule.
Answer:
Explanation:
Answer
The true fact is that C is what happens in outer space. Both rotations take 27.3 days.
A: The exact opposite is true. It does rotate about it's axis.
B: Again this is just plain false. Given the way we observe it, the moon must be rotating around the earth.
D. they don't. 27.3 hours and 24 hours are not the same.