At what height objects will pass each other?

[patelneel1994]

Homework Statement

An object is thrown downward with an initial (t = 0) speed of 10 m/s from a height of 60 m above the ground. At the same instant (t = 0), a second object is propelled vertically upward from ground level with a speed of 40 m/s. At what height above the ground will the two objects pass each other?

first object
t0 = 0
V = 10 m/s
H = 60
Second object
t0 = 0
V = 40 m/s
H = 60

Homework Equations

d = Vi . t + 1/2 a t2

The Attempt at a Solution

This equation doesn't see me to work since we need to find at which height objects will pass

 

[tiny-tim]

hi patelneel1994!

call the height of either object above the ground "d", and rememb
er that the two objects start at different values of d …

show us what you get ​

 

[patelneel1994]

So instead of d I should put h. Find height for each object separately!

 

[tiny-tim]

d or h, it doesn't matter, so long as you use the same symbol for each, but start them at different values

 

[patelneel1994]

I got 41 m. Thanks

 

[haruspex]

I got 41 m. Thanks

I confirm that answer. A slightly quicker way, perhaps, is to note that the two objects undergo the same acceleration, so the relative velocity is constant. The closing speed is therefore a constant 10+40=50 m/s. That tells you how long they take to meet.