SUVAT equations + two balls dropped at different times

[trew]

Homework Statement

two balls dropped

Relevant Equations

suvat

I'm continuing to struggle when it comes to objects that are dropped at different times.

At height h, a ball is dropped at rest.

Also at height h, another ball is dropped one second later.

For the first ball, time=t.

For the second ball, time=t+1...but this is wrong? The answers show it should be: t-1. How?

If I drop ball right now, then the time is t, and if I drop a second ball one second later, then isn't the time t+1?

 

[kuruman]

The SUVAT equations assume that t = 0 when motion starts. Imagine two separate clocks, 1 and 2. Each clock starts when its corresponding mass starts its motion. Write the SUVAT equations as usual using t1 and t2. The latter clock 2 will be behind clock 1 by t0, the time interval between the onset of the two motions. Therefore t1 = t2 + t0 because t1 is a greater number than t2.