Thursday

December 18, 2014

December 18, 2014

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

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!

- physics -
**Denn**, Tuesday, February 12, 2013 at 6:56amWess, there are 2 cases in this prob:

Case 1

U nid to find how long the first rock took to hit the ground: use the formular- s=ut+0.5gt^2 where s=19.6m, u=0, t=?

I gor t=1.97s

Case 2

The second rock took 1.97s-1s to hit the grnd, use same formula & find u

- physics -
**Wes**, Wednesday, February 13, 2013 at 3:40pmThank you very much!

**Answer this Question**

**Related Questions**

PHYSICS- Please Help :( - A ball is thrown downwards at a velocity of 14m/s from...

Physics - Example 1: (Rock A) is thrown against a larger stationary rock(Rock B...

Calc - A rock is thrown upwards (vertically) from the ground with an initial ...

Physics - A rock is thrown vertically from the edge of a cliff that is 500 ft ...

physics - A ball is dropped from a roof to the ground 4.00 m below. Exactly 0....

physics - Consider a rock that is thrown off a bridge of height 27 m at an angle...

Calc - If a rock is thrown upward on the planet Mars with a velocity of 17 m/s, ...

physics - Julie throws a rock vertically upward. From a height of 64.0 meters ...

ALGEBRA - The velocity v (in feet per second) of a rock dropped into a well is ...

Physics - Two rocks are thrown off the edge of a cliff that is 15.0 m above the ...