Doubts in Physics answered

Home » Ask Physics » Another problem from kinematics

Username

Password

Remember Me

AskPhysics on FB

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

Join 3,871 other subscribers

Email Address

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

Tags: 10m, air resistance, answer, ask Physics, Auto, Draft, physics, problem, relation, resistance, time, Water

here we have to use Newton’s equations of motion.

Post your Physics Doubts here

Ask Physics @askphysics

here we have to use Newton’s equations of motion.