acceleration is the rate of change of velocity
the speed has increased from 5 m/s to 7.5 m/s over a period of 1.25 s
the formula to calculate acceleration is as follows
[tex] a = \frac{v-u}{t} [/tex]
where a - acceleration
u - initial velocity
v - final velocity
t - time
substituting the values in the equation
[tex] a = \frac{7.5 m/s - 5.0 m/s}{1.25 s} = \frac{2.5}{1.25} = 2 [/tex]
acceleration is 2 m/s²