Question -
Answer -
(a) 1 kg = 103 g
1 m2 = 104 cm2
1 kg m2 s–2 = 1 kg × 1 m2 ×1 s–2
=103 g × 104 cm2 ×1 s–2 = 107 g cm2 s–2
(b) Light year is the total distance travelled by light in oneyear.
1 ly = Speed of light × One year
= (3 × 108 m/s) × (365 × 24 × 60 × 60 s)
= 9.46 × 1015 m
(c) 1 m = 10–3 km
Again,1 s =
1 s–1 = 3600 h–1
1 s–2 = (3600)2 h–2
∴3 m s–2 = (3 × 10–3 km)× ((3600)2 h–2) = 3.88 × 104 kmh–2
(d) 1 N = 1 kg m s–2
1 kg = 10–3 g–1
1 m3 = 106 cm3
∴ 6.67 × 10–11 N m2 kg–2 =6.67 × 10–11 × (1 kg m s–2) (1 m2) (1 s–2)
= 6.67 × 10–11 × (1 kg × 1 m3 × 1s–2)
= 6.67 × 10–11 × (10–3 g–1)× (106 cm3) × (1 s–2)
= 6.67 × 10–8 cm3 s–2 g–1