Question

Alligators and other reptiles don't use enough metabolic energy to keep their body temperatures constant. they cool off at night and must warm up in the sun in the morning. suppose a 300 kg alligator with an early-morning body temperature of 25?c is absorbing radiation from the sun at a rate of 1200 w.

Answer 1

To compute for the heat, $Q$ needed to be absorbed or released,  we need

$Q = mc\Delta T$

where $m$ is the mass of the alligator, $\Delta T$ is the change in temperature, and $c$ is the specific heat of the alligator's body. Plugging in all the information we have,

$Q = (300 kg)(3400 kJ/K)(30-25) = 5100000 J$

Recall that 1 Watt = 1 J/s, thus time needed to absorb radiation from the sun is

$t = \frac{Q}{W}\\ t = 4250 seconds$

That means it takes 4250 seconds for the alligator to warm up to be able to absorb the radiation from the sun.

Answer: 4250 seconds