Calculating Time for Object B to Catch Object A in Constant Velocity Motion

[Kandy]

Object A travels at a constant velocity af 2.0 m/s east, and object B travels in the same direction at a constant velocity of 3.0 m/s. If object B starts 1.0 min after object A, how long (time) will it take object B to catch object A?

 

[cscott]

Object A travels at a constant velocity af 2.0 m/s east, and object B travels in the same direction at a constant velocity of 3.0 m/s. If object B starts 1.0 min after object A, how long (time) will it take object B to catch object A?

You're dealing with constant velocity so you know d = vt applies.

Object A

d_A = 2.0t

Object B

d_B = 3.0(t + 1.0)

Because object B is going to catch object A, the distance will be the same. Can you take it from here?

 

[Kandy]

I don't quite get it, but this is what I tried:

d_B = 3.0(t+1.0)
= 3.0t+3.0

d_A = d_B
2.0t = 3.0t+3.0
-1.0t = 3.0
t=-3.0

but the answer key shows 1.2 x 10^2 s (2.0 min not -3.0 min)
sorry, but i need more help.