Subject Experts Solutions for Chapter: Our Universe, Exercise 2: PRACTICE QUESTIONS (COMPETITION WING)

Why do planets revolve around the sun?

Explain why the number of meteorites striking the surface of moon is quite large whereas very few reach the surface of the earth even though the gravitational force of attraction of moon is less than that of the earth.

How does a perfume sprayer work?

What is the relation between the force of gravitation on the moon and on the earth? Consider a body of mass m on the surface of earth. What will be the relation between its mass and weight with that on the moon?

An object is made to float in two immiscible liquids as shown in the figure. Compare the densities of two liquids A and B and the object.

The gravitational attraction of the earth on any object is proportional to its mass. Then why do heavy objects not fall faster than light objects?

A lighted candle is placed inside a rectangular box having two holes at its top, and a wheel made up of paper is placed inside it as shown in the figure. In which direction will the wheel rotate ? Why?

The value of universal gravitational constant$\left(G\right)$ in MKS system is $6.67\times {10}^{-11} \mathrm{N} {\mathrm{m}}^2 {\mathrm{kg}}^2$. Find its value in C.G.S. system. What will be the change in the value of $G$ if the masses of two bodies is doubled and the distance between them is halved?