Answer:
D - The elevator traveled upward at a rate of 2(2/5) feet per second.
Explanation:
Okay, this is almost like kinematics, which deals with physics.
Here are your given values:
Position 1 = 70ft [down]
Position 2 = 10ft [down]
Change in time (Δt - time - scalar) = 25 seconds
The equation for displacement is d₂-d₁. This would be the change of position of the elevator during the 25 seconds.
So, we can use this equation to figure out the change in position.
Δd = d₂-d₁ = 10ft [down] - 70 ft [down] = 60ft [up]
The equation for velocity is Δd/Δt. This would be the rate of which the elevator travels. Velocity is simply speed but with a direction.
So, we can use this equation to solve.
v = Δd / Δt = 60 feet [up] / 25 seconds = 2.4 ft / second [up].
Now, we need to change 2.4 ft / second [up] into a fraction.
2.4 -> 2 (4/10) -> 2 (2/5)
All I am simply doing is figuring out the distance the elevator traveled and determined the direction of which the elevator traveled. Then, I divided that by the time the elevator traveled to determine its speed and the direction the elevator traveled.