Answer:
Step-by-step explanation:
It doesn't look like you have enough information. What you do in that case is to use a known mass.
m = 4
a = 12.0 m/s^2
F = m * a
F = 4 * 12
F = 48 N
Now you multiply the force by 4 and solve for a. The mass is left at 4
F = 48*4
F = 192
F = 192
m = 4
a = ?
192 = 4 * a Divide by 4
192/4 = a
a = 48 m/s^2