Gravitation — Physics STD 11 Science — Question

The density of oxygen is 16 times the density of hydrogen. What is the relation between the speeds of sound in two gases?

Why do aeroplanes having wings fly at low altitudes?

A body is acted upon by a number of external forces. Can it remain at rest?

Explain why (or how):
A violin note and sitar note may have the same frequency, yet we can distinguish between the two notes,

Write the relationship between co-efficient of volume expansion and co-efficient of linear expansion.

Answer the following : There were two fixed points in the original Celsius scale as mentioned above which were assigned the number 0°C and 100°C respectively. On the absolute scale, one of the fixed points is the triple-point of water, which on the Kelvin absolute scale is assigned the number 273.16 K. What is the other fixed point on this (Kelvin) scale?

A body falling from a height of 10m rebounds from a hard floor. It loses 20% of its energy in impact. What is the height to which it would rise after the impact?

A scooter weighing 150kg together with its rider moving at 36km/ hr is to take a turn of radius 30m. What horizontal force on the scooter is needed to make the turn possible?