Question

For a scientific experiment, a physicist must make sure that the temperature of a metal at 0 °C gets no colder than -80 °C. The physicist changes the metal’s temperature at a steady rate of -4 °C per hour.

c. The physicist has to repeat the experiment if the metal gets cooler than -80 °C. How many hours would the physicist have to cool the metal for this to happen?
a) 20 hours
b) 40 hours
c) 60 hours
d) 80 hours

Answer 1

The physicist would have to cool the metal for a minimum of 20 hours for its temperature to reach below -80 °C.

Step-by-step explanation:

To determine how many hours the physicist would have to cool the metal for it to reach a temperature below -80 °C, we can set up an equation using the given information.

We know that the physicist changes the metal's temperature at a rate of -4 °C per hour. So, we can set up the equation: -4h ≤ -80, where h represents the number of hours.

Solving this equation, we find that h ≥ 20. Therefore, the physicist would have to cool the metal for a minimum of 20 hours for its temperature to reach below -80 °C.