The elevation at ground level is 0 feet. an elevator starts 90 feet below ground level. after traveling for 15 seconds, the elevator is 20 feet below ground level. which statement describes the elevators rate of change during this 15 second interval?
a. the elevator traveled upward at a rate of 6 ft per second
b. the elevator traveled upward at a rate of 4 2/3 feet per second.
c. the elevator traveled downward at a rate of 6ft per second.
d. the elevator traveled downward at a rate of 4 2/3 feet per second
So, we say at time, t = 0, the elevator just starts moving upwards and at time t = 0, the elevator is 90 ft below the ground.
Now, after 15 seconds, the elevator is 20 ft below the ground.
It means, the elevator has covered a distance of 90-20=70 ft in time 15 seconds.
So, speed of elevator moving upwards is:
i believe the answer is 7.33333333333 feet per second
If we graph elevation vs time, the rate of change is the slope of the line.
At t = 0, h = -90.
At t = 15, h = -20.
m = (-20 − (-90)) / (15 − 0)
m = 70/15
m = 4.67
The closest answer is B. The elevator traveled upward at a rate of 4 feet per second.
Unfortunately there was no choice in which we can choose our answer to this item. However, looking into the situation given in this item, it may be deduced that the distance traveled by the elevator after 15 seconds is equal to 70 ft. The rate of change in elevation of the elevator is therefore 70ft/15s which is also equal to 4.67 ft/s.