How High Did the Object Fall If It Took 1.5 Seconds to Drop the Last 30 Meters?

[jaypea65]

Homework Statement

A certain freely falling object requires 1.50 sec to travel the last 30 m before it hits the ground. From what height above the ground did it fall?

Homework Equations

The Attempt at a Solution

the answer is 38.2, but I cannot figure out what formula to use to get there.

 

[LowlyPion]

Homework Statement

A certain freely falling object requires 1.50 sec to travel the last 30 m before it hits the ground. From what height above the ground did it fall?

Homework Equations

The Attempt at a Solution

the answer is 38.2, but I cannot figure out what formula to use to get there.

Welcome to PF.

Here are some equations for relating x, v, t, a.

https://www.physicsforums.com/showpost.php?p=905663&postcount=2

Maybe you can get an idea.

 

[baba89]

I would approach this problem by using the equation for free fall motion, which is:

d = 1/2 * g * t^2

Where d is the distance, g is the acceleration due to gravity (9.8 m/s^2), and t is the time.

We are given the time (1.50 sec) and the distance (30 m), so we can plug those values into the equation and solve for the initial height (h).

30 = 1/2 * 9.8 * (1.50)^2

30 = 1/2 * 9.8 * 2.25

30 = 11.025

h = 30 - 11.025

h = 38.2 meters

Therefore, the object fell from a height of 38.2 meters.