Remark
Usually this is written in very simple terms. You could do it as a proportion, but it might be easier to see if you used Newton's formula twice.
Formula
F = m * a
m = mass, F = force, a = accelerationn
Givens
F1 = 70 N
a1 = 6.5 m/s^2
m = ?
F2 = ??
m = ?
a2 = 8 m/s^2
Step One
Solve for m
F1 = m * a1 Substitute the values
70 = m * 6.5 Divide by 6.5
70/6.5 = m
10.77 kg = m
Step Two
Solve for F2
m = 10.77 kg
a = 8
F2 = ??
F2 = m * a2
F2 = 10.77 * 8
F2 = 86.154
Answer: C rounded to the nearest 1/100
