Each of the four particles move along an x axis. Their coordinates (in metres) as function of time (in seconds) are given by Particle 1 : x(t) = 3.5 - 2.7`t^3` Particle 2 : x(t) = 3.5 + 2.7`t^3` Particle 3 : x(t) = 3.5 + 2.7`t^2` Particle 4 : x(t) = 2.5 - 3.4t - 2.7 `t^2` which of these particles is speeding up for t > 0?

Options

A. All four
B. Only 1
C. only 1,2, and 3
D. only 2,3 and 4

Answer

A