Answer
(a) (i) $v = 3.7 \space m/s$ and $E_k = 0.0069 \space J$
(ii) $v = 11 \space m/s$ and $E_k = 0.062 \space J$
Work Step by Step
(i) $$v = at \longrightarrow v = (3.72 \space m/s^2)(1.0 \space s) = 3.72 \space m/s =* 3.7 \space m/s$$ $$E_k = \frac 12 mv^2 = \frac 12 (1.0 \space g)(3.72 \space m/s)^2 = 6.9 \space g \space m^2/s^2 \times \frac{1 \space kg}{1000 \space g} = 0.0069 \space kg \space m^2/s^2 = 0.0069 \space J$$
(ii) $$v = at \longrightarrow v = (3.72 \space m/s^2)(3.0 \space s) = 11.16 \space m/s =* 11 \space m/s$$ $$E_k = \frac 12 mv^2 = \frac 12 (1.0 \space g)(11.16 \space m/s)^2 = 62 \space g \space m^2/s^2 \times \frac{1 \space kg}{1000 \space g} = 0.062 \space kg \space m^2/s^2 = 0.062 \space J$$
* Correct number of significant figures.
