A wooden log is displaced to a distance of 20m in 10 seconds by applying 500N effort . Calculate the workdone and power...
Solution,
displacement = 20 m
time = 10 sec
force = 500 N
work done = ?
power = ?
Now ,
work done = f × s
= 500 N × 20 m
= 10000 j
Now ,

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Answer:


Explanation:
A denotes Alex
M denotes Mary
r = Distance from center
Mary and Alex will have the equal displacements in equal interval of time as they are in uniform circular motion. So,

Tangential speed speed is given by

The tangential speed of Mary is 
The total mechanical energy of the block-spring system is given by the sum of the potential energy and the kinetic energy of the block:

where
k is the spring constant
x is the elongation/compression of the spring
m is the mass of the block
v is the speed of the block
At the point of maximum displacement of the spring, the velocity of the block is zero: v=0, so the kinetic energy is zero and the mechanical energy is just potential energy of the spring:

(1)
where we used x=A, the amplitude (which is the maximum displacement of the spring).
Since we know
A = 11.0 cm= 0.11 m
E = 1.10 J
We can re-arrange (1) to find the spring constant:
Convection. When a fluid such as air or water touches a hot object, it can heat up and then move in bulk as a fluid, thereby carrying the heat quickly to new locations. Hot air rising is a common example of heat convection.
Increasing the masses of the objects and decreasing the distance between the objects