Free Fall Problem - Please Just Check Work

[Rker]

Homework Statement

A bolt comes loose from the bottom of an elevator when it is at a height of 15 m above the bottom of the elevator shaft. If the elevator is originally moving upward at a speed of 7.5 m/sec, assuming that the elevator continues to ascend at a constant speed, how high above the ground will the elevator be when the bolt reaches the ground.

Homework Equations

Seen in attempt.

The Attempt at a Solution

I am graded X/10 based on whether my answer is correct and if I show all work possible for this problem.

 

[jbsteele]

Let's assign the following variables:Initial Elevator Height = hElevator Speed = vTime = tFinal Elevator Height = h'h + vt = h' h = 15 m v = 7.5 m/sec t = ? h' = ? We can solve for t by rearranging the equation and plugging in our known values:h' - h = vt 15 - 0 = 7.5t t = 2 seconds Now we can plug this back into the original equation to calculate h':h' = h + vt h' = 15 + (7.5)(2) h' = 30 m So the elevator will be 30 meters above the ground when the bolt reaches the ground.