Wednesday
April 16, 2014

Homework Help: physics

Posted by Wes on Sunday, February 10, 2013 at 7:00pm.

A rock is dropped from a treetop 19.6 m high, and then,
1.00 s later, a second rock is thrown down. With what
initial velocity must the second rock be thrown if it is to
reach the ground at the same time as the first?

I'm not sure how to find the initial velocity of the thrown rock, since it's not 0

What I have so far:

1st rock:
Yo=o
Yf=19.6 m
Vo=o
Vf=
T=
A= -9.80 m/s^2

I think I've found the final velocity and time of the 1st rock
(Vf^2=Vo^2-2g(Y-Yo)
or final velocity squared = initial velocity(0 m/s)^2 -2(9.80)(-19.6-0)
which is = to -19.6 m/s
Time = 2 seconds
(Vf=Vo-gt, Vf/Vo-g=T, -19.6 m/s /-9.80 m/s^2, 2 seconds

How do I find the initial velocity of a throw object when I know:
Yo=o
Yf=19.6 m
T= 2-1 = 1 second
A- /9.80 m/s^2

Thanks!

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

Physics - One can get a good idea of how deep a well is, for example, by ...
Physics - A rock is dropped from a sea cliff 400m high.If the speed of sound is ...
Physics - A small parachute is dropped from a cliff. it falls at a constant ...
physics - A rock dropped from an airplane falls for 13.6 seconds before hitting ...
Physics - acceleration due to gravity questions A rock is dropped from a height ...
physics - a rock is dropped off a cliff. after 4s, what is the rocks velocity? ...
physics - A rock is dropped. How fast will the 5.0 kg rock be traveling in 4.0s ...
physics - A rock is dropped from rest off a cliff to the surface of a lake which...
PHYSICS- Please Help :( - A ball is thrown downwards at a velocity of 14m/s from...
Physics - if rock A is dropped from a cliff and rock B is thrown downward off ...

Search
Members