Why is it dangerous to jump out of a moving bus?

Why are space crafts usually launched from west to east? Why is it more advantageous to launch rockets in the equatorial plane

Why is it cooler at the top of mountains?

Why is meta centre?

Why is it difficult to walk on ice ?

When several passengers are standing in a moving bus, it is said to be dangerous. How will you justify this statement?

A trolley of mass 200 kg moves with a uniform speed of 36 km/ h on a frictionless track. A child of mass 20 kg runs on the trolley from one end to the other (10 m away) with a speed of 4 m s^-1 relative to the trolley in a direction opposite to the its motion, and jumps out of the trolley. What is the final speed of the trolley? How much has the trolley moved from the time the child begins to run?

Explain why earth's magnetic field does not affect the working of a moving coil galvano meter.

What is the radius of the path of an electron moving at a speed of 10^7m//s in a magnetic field of 2xx10^(-4) T perpendicular to it? Also find out its frequency and energy.

Why is friction essential ?