Question

answer the questions below.
note that a change can be an increase or a decrease.
for an increase, use a positive number.
for a decrease, use a negative number.
(a) a tram moved downward 40 meters in 8 seconds at a constant rate. what was the change in
the tram’s elevation each second?
meters
(b) in a lab, a substance was heated by 4 °c each hour for 28 hours. what was the total change
in temperature?
°c

Explanation:

Step1: Solve part (a)

The train moves downward 40 meters in 8 seconds. Downward is a decrease, so we use a negative number for the rate? Wait, no, first find the rate per second. The total change in elevation is -40 meters (downward) over 8 seconds. Wait, no, the question is "What was the change in the train’s elevation each second?" So we divide the total change ( -40 meters) by time (8 seconds). So \(\frac{-40}{8} = -5\) meters per second. Wait, but maybe the problem is asking for the total change? Wait, no, the wording: "A train moved downward 40 meters in 8 seconds at a constant rate. What was the change in the train’s elevation each second?" So each second, the change is total change divided by time. Total change is -40 meters (downward), time is 8 seconds. So \(\frac{-40}{8} = -5\) meters per second. So the change each second is -5 meters.

Step2: Solve part (b)

A substance is heated by \(4^\circ\)C each hour for 28 hours. Heating is an increase, so positive. Total change is rate times time: \(4 \times 28 = 112\) \(^\circ\)C.

Answer:

(a) The change in the train’s elevation each second is \(-5\) meters.
(b) The total change in temperature is \(112\) \(^\circ\)C.