- #1

Secretdude

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## Homework Statement

A ball is tossed from 1m above the ground to a total height of 12m. An unidentified object passes directly underneath it at 20m/s at a height of 1m. If the ball lands on the object as it passes underneath, how far away was the unidentified object when the ball was tossed? What was the ball's velocity as it was tossed?

Also, I need to find velocities and distances relative to each object (ball, tosser, unidentified object). This is where the problems lie, if there are any.

__Ball (to peak)__

V

_{iy}=?

V

_{fy}=0

a=-9.81m/s

^{2}

y=11m

__Ball (fall)__

V

_{iy}=0

y=-11m

__Object__

V=20m/s

d=?

__Tosser__

V=0

d=0

## Homework Equations

There are quite a few of these...

Vf

^{2}=Vi

^{2}+2ad

Vf=Vi+at

d=vt

d=Vit+.5at

^{2}

Not sure if I need these...

hmax=(Vo

^{2}sin

^{2}ø)/2g

R=(Vo

^{2}sin(2ø))/g

Then there was one for time of flight, as well as some relating x and y and Vix and Viy to sin and cos, but I don't remember them off the top of my head. :(

## The Attempt at a Solution

Using a pair of the two formulas above, I got the fall time to be 1.497s, so total toss and fall time should 2.995s. I got distance to 59.9m. Unfortunately I don't have my papers with me at the moment and I don't remember what I got for Vi.

In addition to finding these, I must construct three pictures: one of what the ball sees, one the tosser sees, and one the unidentified object sees.

The tosser's is simple: ball goes up and comes back down, unidentified object moves under the ball.

The ball's may be a problem: the ball "sees" the tosser go down, then come back up. The unidentified object appears to dip down, the come back up under the ball, correct? Because the ball is the point of reference, how fast does the unidentified object appear to move?

Unknown object: Tosser lays flat on the ground and moves at 20 m/s at the unknown object. The ball appears to have been thrown up so that it appears to move in a semicircle. How fast does the ball travel in each direction?

I think that's everything. If something's missing I can get it tomorrow. This is a made-up problem for a project so there'll probably be something wrong with it.