A Physics Question! Please Answer!?

Question

A body at rest measures the acceleration a body A as 4 meter\second square.

Another body B moving with 10 meter\second square towards body A will measure the acceleration of body A as.....?

Answer 1

14m/s

Answer 2

Because the bodies are both accelerating towards one another, add the respective acceleration rates:

10m/s²+4m/s² = 14ms²

Answer 3

Body B is moving at a constant velocity and that will not affect the acceleration of body A.  It will measure the acceleration to be 4 m/s2.  If you think of it as being far away and consider body B to be measuring its relative velocity, at time 0, it will be -10 m/s, at time 1 it will be -6 m/s, at time 2 it will be -2 m/s, and at time 3 it will be 2 m/s.  So, it is still accelerating 4 m/s every second.