# Object falling down and object falling up

## Homework Statement

A object A falling down at terminal velocity of 20 m/s, at 1000m above the ground another object B fly at it at an initial velocity of 125 m/s.

a) how much time before object A hits object B?

## Homework Equations

X = Xo + Vo(t) + 1/2AT^2

G = 9.8 m/s^2

## The Attempt at a Solution

using the equation i found it takes object A 12.385 second to fall down from 1000
m while object B 6.321 second to reach 1000 m

but im not sure how i can find out when they will hit each other.

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rl.bhat
Homework Helper
Suppose they meet at a height x from the ground. Then the distance moved by A is 1000 - x and distance move by B is x. A is moving with uniform velocity where as B is moving with the acceleration. When they meet, they must have taken the same time. So write two equations and solve for x.

SammyS
Staff Emeritus
Homework Helper
Gold Member
Does an object falling at terminal velocity accelerate? Why not?

So, you time for object A is incorrect.

Object B will not reach a height of 1000 m.

An object launched downward at 125 m/s from a 1000 m altitude, will reach the ground in 6.396 s, ignoring air resistance.

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