If you stand facing forward during a bus or subway ride, why does a quick deceleration topple you forward and a quick increase in speed throw you backward ? Why do you have better balance if you face toward the side of the 'bus or" subway train?

Have you ever sung in the shower ? Why does your voice sound so much better there.

Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?

When a tan stasrts, the head of a standing passenger seems to be pushed backward. Analyse the situation from the ground frame. Does it really go backward? Coming back to the train frame, how do you explain the backward movement of the head on the basis of Newton's laws?

Try this Material: Convex lens, screen, metre scale, stand for the lens etc. Method: Keeping the screen fixed, obtain a clear image of a distant object like a tree or a building with the help of the lens on the screen. Measure the distance between the screen and the lens with the help of the metre scale. Now tum the other side of the lens towards the screen. Again obtain a clear image of the distant object on the screen by moving the lens forward or backward. Measure the distance between the screen and the lens again. What will happen if you use a concave lens in this experiment?