Solution:

(a) 5000 g
= $5 \times 1000g$         
= $5 \times 1kg  (Since 1000g = 1kg)$
= 5kg

(b) 2000,000 w
=$2 \times 1000000$
= $2 \times 10^{6}W  (10^{6} = 1 Mega)$
= 2 MW

(c) $52 \times 10^{-10} kg$
= $5.2 \times l0\times 10^{-10}kg$
= $5.2 \times 10^{-9} kg$
= $5.2 \times10^{-9} \times 1000g$      (Since 1 kg = 1000 g)
= $5.2\times 10^{-9} \times 10^{3} g$
= $5.2\times 10^{-9} \times 10^{-6} g$
= $5.2 µg  (10^{-6} = 1micro(µ))$

(d) $225 \times 10^{-8} s$
= $225\times10^{2} \times 10^{-8} s$
= $2.25 \times 10^{-6} s$
= $2.25 µs   (10^{-6} = 1micro(µ))$