#### Answer

(a) $a = 16~m/s^2$
(b) $a = 4.0~m/s^2$
(c) $a = 8.0~m/s^2$
(d) $a = 32~m/s^2$

#### Work Step by Step

$F = ma$ can be written as:
$a = \frac{F}{m}$
Then, we find $a$:
$a = \frac{F}{m} = 8.0~m/s^2$
(a) $a = \frac{(2F)}{m} = (2)(8.0~m/s^2) = 16~m/s^2$
(b) $a = \frac{F}{(2m)} = \frac{8.0~m/s^2}{2} = 4.0~m/s^2$
(c) $a = \frac{(2F)}{(2m)} = \frac{F}{m} = 8.0~m/s^2$
(d) $a = \frac{(2F)}{(m/2)} = \frac{4F}{m} = (4)(8.0~m/s^2) = 32~m/s^2$