object stable? frame on earth, what will be the 0.5m 0.25 3 ss on moon fa liquid can be determined Total: 0 e calculated. Figure 4.1 (a) What is meant by moment of force? Include its Sl unit? [2] (c) Calculate the moment of force if a force of 10N is applied at point 1 to open or close the door. mass of 35g When filled wit Moment of force=_ [2] (d) Explain why it is easier to open or close the door if the handle is fixed at point 1 than at point 2 or 3. aters sity of water to be [2] Total:[4] ettler Total : (4​

graph slopes whilst gas cools, then it is flat whilst conensation to liquid happens, the coolong liquid then graphs as a slope when it solidifies graph is flat

latent heat

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.