Heya!!
For calculate aceleration, lets applicate second law of Newton:
[tex]\boxed{F=ma}[/tex]
Δ Being Δ
F = Force = 15 N
m = mass = 0,25 kg
a = Aceleration = ?
⇒ Let's replace according the formula:
[tex]\boxed{15\ N = 0,25\ kg * \textbf{a}}[/tex]
⇒ Let's clear acceleration and resolve it:
[tex]\boxed{\textbf{a}=60\ m/s^{2}}}[/tex]
Result:
The aceleration is of 60 meters per second squared (m/s²)
Good Luck!!