A 40W lamp wastes 34 J of energy every second by heating its surroundings.
1 answer:
Answer:
.
Explanation:
The efficiency of a machine is the percentage of energy input that was turned into useful energy.
The power rating of this lamp is (same as
,) meaning that
of energy is supplied to this lamp every second.
The question states that out of that
of energy input would be turned into heat, which is not useful energy output in this scenario. Assuming that all other forms of energy loss is negligible. The rest of the
of energy supplied to this lamp would be turned into useful energy output.
Thus, every second, this lamp would receive of energy input and would outputs
of useful work. The efficiency of this lamp would be:
.
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Answer:
Max speed =
Max acceleration =
Explanation:
Given the description of period and amplitude, the SHM could be described by:
and its angular velocity can be calculated doing the derivative:
And therefore, the tangential velocity is calculated by multiplying this expression times the radius of the movement (3 m):
and is given in m/s.
Then the maximum speed is obtained when the cosine function becomes "1", and that gives:
Max speed =
The acceleration is found from the derivative of the velocity expression, and therefore given by:
and the maximum of the function will be obtained when the sine expression becomes "-1", which will render:
Max acceleration =