Question: "A 100-watt light bulb uses how many joules..."

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TokNeekCepTdh

Answered question

2021-11-24

A 100-watt light bulb uses how many joules of energy every hour? How quickly would a 70-kg person need to move in order to expend that much kinetic energy?

Answer & Explanation

Lible1953

Beginner2021-11-25Added 16 answers

Based on the relationship between power and energy, $P = \frac{W}{△ t ‘}$
calculate W, the amount of energy that the lightbulb consumes
Then, $W = K = \frac{1}{2} m v^{2}$
and solve for speed,
$W = P Δ$ $t = (100 W) (3600 s) = 3.6 \times 10^{5} J$
$K = 3.6 \times 10^{5} J$
$v = \sqrt{\frac{2 K}{m}} = \sqrt{\frac{2 (3.6 \times 10^{5} J)}{70 k g}} = 100 \frac{m}{s}$
Result
$100 \frac{m}{s}$

Cherry McCormick

Beginner2021-11-26Added 23 answers

Given data:
Power of the light bulb $P = 100 W$
mass of the person $m = 70 k g$
Time $t = 1 h = 3600 s$
The equation for the relationship between power and energy is,
$P = \frac{W}{t}$
where W is the work done in joule
and t is the time
Therefore,
$W = P t = (100 W) (3600 s)$
$W = 3.6 \times 10^{5} J$
$\frac{1}{2} m v^{2}$
$v = \sqrt{\frac{2 W}{m}} = \sqrt{\frac{2 \times 3.6 \times 10^{5}}{70}}$
$v = 100 \frac{m}{s}$

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