An athlete at the gym holds a 2.5 kg steel ball in his hand. His arm is 70 cm long and has a mass of 4.0 kg.
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Answer:
Explanation:
The power delivered in the wire is given by:
where V is the voltage of the battery and R is the resistance of the wire.
Since the voltage of the battery is constant, we can rewrite this equation as follows:
(1)
At the beginning, the initial resistance is , and the power delivered is
. Later, when the temperature increases, the power becomes
, and the new resistance is
. Using (1), we can write
(2)
So, the new resistance must be 3/2 of the initial resistance.
We know that the resistance increases linearly with the temperature, as
where
is the temperature coefficient
is the change in temperature
Using (2), we can rewrite this equation as
and we find:
So, the new temperature of the wire must be