(c) A vehicle moving with a speed of 18 km h^–1 covers….m in 1

(d) The relative density of lead is 11.3. Its density is ….g cm^–3 or ….kg m^–3.

Answer:

(c) Given, speed of the vehicle = 18 km/h

We know that 1 km = 1000 m and 1 hr = 60 x 60 = 3600 s

Therefore, 1 km/hr = 1000 m/3600 s

1 km/hr = 5/18 m/s

Similarly, 18 km/h = (18 x 1000)/3600
!8km/h = 5 m/s

Therefore, the distance travelled by the vehicle in 1 s is 5 m.

(d) Given that the relative density of lead is 11.3 g cm^-3

=> 11.3 x 10³ kg m^-3 

We know that 1 kilogram = 10³g, 1 meter = 10² cm

Therefore, 11.3 x 10³ kg m^-4