A sphere of mass 40 kg is attracted by another sphere of mass 15 kg with a force of 9.8×10 power -7 N. Find the value of the universal gravitational constant if the centres of spheres are 20cm apart [ Take g=10m/s square and G=6.67×10 power-7 Nm square kg -square

because if the tool that you are using is not balanced it there would be false mass.

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.