Iqra N.

asked • 10/20/17

Rock thrown vertically down. Find the time taken

A girl on a bridge throws a rock straight down at -12.5 m/s. It hits the ground 38.4 m below.
How much time did it take ?

1 Expert Answer

By:

Arturo O. answered • 10/20/17

Tutor
5.0 (66)

Experienced Physics Teacher for Physics Tutoring

See tutors like this
See tutors like this
Δy = (1/2)gt2 + vt = 4.9t2 + 12.5t
 
Δy = 38.4
 
4.9t2 + 12.5t - 38.4 = 0
 
t = 1.80 s
 
 
Upvote • 0 Downvote
More
Report

Iqra N.

Thank you very much for the solution, but the answer given is 1.08 s.
Report

10/23/17

Arturo O.

Solve the quadratic equation and see that 1.80 is the correct solution, rounded to 2 decimal places.  I suspect that 1.08 is a typo.  Where did that number come from?
Report

10/23/17

Still looking for help? Get the right answer, fast.

Ask a question for free

Get a free answer to a quick problem.
Most questions answered within 4 hours.

OR

Find an Online Tutor Now

Choose an expert and meet online. No packages or subscriptions, pay only for the time you need.