Home » Ask Physics » Another problem from kinematics

Another problem from kinematics

Zeen asks:

A boy jumps from rest, straight down from the top of a cliff. He falls halfway down to the water below in 0.800 s. How much time passes during his entire trip from the top down to the water? Ignore air resistance.

Answer :

let the total height be h

So, for first case

S = h/2

a = g=10 m/s^2

u=0 m/s

t = 0.8 sec

using the relation

h/2 = 0.5 x 10×0.8 ^2

h=6.4 m

In second case (considering the full motion)

S=h=6.4m

t=?

a=g=10m/s^2

u=o m/s

using the relation 
6.4 = 0.5 x 10 x t^2

or

t = 2 x 6.4/10 = 1.28 s


1 Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Hits so far @ AskPhysics

  • 2,274,296 hits

You may also be interested in

Subscribe to AskPhysics via Email

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 4,338 other subscribers

June 2021
M T W T F S S
 123456
78910111213
14151617181920
21222324252627
282930  

Learn Self Defence Techniques online

%d bloggers like this: