- #1

Adjoint

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[EDITED. Thanks to Doc Al, Tanya Sharma and dauto]

A ball is dropped from rest from the top of a building of

height h. At the same instant, a second ball is projected vertically

upward from ground level, such that it has zero speed when it

reaches the top of the building.

(A) At the time when the two balls pass each other -

which ball has the greater speed, or do they have the same speed?

(B) Where will the two balls be when they are alongside each

other: at height h/2 above the ground, below this height, or above

this height?

Equations of 1D motion for a constant acceleration of

First here is the diagram I drew:

I suppose that the second ball was thrown up with velocity v

And the balls pass each other at time t

So for the first ball v = -gt

And for the second ball v = v

So speed of the first ball |-gt|

Speed of the second ball |v

Now which one is greater? How can I tell??

I shall post my attempt for second part later but someone please help me deal with this.

Thanks in advance!

## Homework Statement

A ball is dropped from rest from the top of a building of

height h. At the same instant, a second ball is projected vertically

upward from ground level, such that it has zero speed when it

reaches the top of the building.

(A) At the time when the two balls pass each other -

which ball has the greater speed, or do they have the same speed?

(B) Where will the two balls be when they are alongside each

other: at height h/2 above the ground, below this height, or above

this height?

## Homework Equations

Equations of 1D motion for a constant acceleration of

**-**g## The Attempt at a Solution

First here is the diagram I drew:

*Now for part (A)*:I suppose that the second ball was thrown up with velocity v

_{0}And the balls pass each other at time t

So for the first ball v = -gt

And for the second ball v = v

_{0}-gtSo speed of the first ball |-gt|

Speed of the second ball |v

_{0}-gt|Now which one is greater? How can I tell??

I shall post my attempt for second part later but someone please help me deal with this.

Thanks in advance!

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