18. (a) Repulsion is the only test of polarity of a magnet. Explain.

Infrared rays have a shorter wavelength than question 11 options: x-rays. ultraviolet rays. radio waves. gamma rays.

3. a lunar exploration vehicle was created by a research team. it weighs 3,000 kg on the earth. it needs an acceleration of 10 m/s2 on the moon. in order to have the same acceleration, what will be the net force acting on the vehicle on the earth?

2) why do satelites not fall while revolving around the earth?