Answer:
0.031 W
Explanation:
The power used is equal to the rate of work done:
where
P is the power
W is the work done
t is the time taken to do the work W
In this problem, we have:
W = 900 J is the work done by the motor
t = 8 h is the time taken
We have to convert the time into SI units; keeping in mind that
1 hour = 3600 s
We have
And therefore, the power used is
The potential energy of the block is A) 490 J
Explanation:
The potential energy of an object is the energy possessed by the object due to its position in the gravitational field.
It is calculated as follows:
where
m is the mass of the object
g is the acceleration due to gravity
h is the height of the object above the ground
For the block in this problem, we have:
m = 10 kg
h = 5 m
Therefore, its potential energy is:
Learn more about potential energy:
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