H C Verma Solutions for Chapter: The Forces, Exercise 4: EXERCISES

A monkey is sitting on a tree limb. The limb exerts a normal force of $48 \mathrm{N}$ and a frictional force of $20 \mathrm{N}$. Find the magnitude of the total force exerted by the limb on the monkey.

A bodybuilder exerts a force of $150 \mathrm{N}$ against a bullworker and compresses it by $20 \mathrm{cm}$. Calculate the spring constant of the spring in the bullworker.

A satellite is projected vertically upwards from an Earth station. At what height above the Earth's surface will the force on the satellite, due to the Earth be reduced to half of its value at the Earth station? (Radius of the Earth is $6400 \mathrm{km}$)

Two charged particles placed at a separation of $20 \mathrm{cm}$ exert $20 \mathrm{N}$ of Coulomb's force on each other. What will be the force, if the separation is increased to $25 \mathrm{cm}$?

The force with which the Earth attracts an object is called the weight of the object. Calculate the weight of the Moon from the following data.

1. The universal constant of gravitation is $G=6.67\times {10}^{-11} \mathrm{N} {\mathrm{m}}^2 {\mathrm{kg}}^{-2}$.

2. Mass of the Moon is $7.36\times {10}^{22} \mathrm{kg}$.

3. Mass of the Earth is $6\times {10}^{24} \mathrm{kg}$.

4. The distance between the Earth and the Moon is $3.8\times {10}^5 \mathrm{km}$.

Find the ratio of the magnitude of the electric force to the gravitational force acting between two protons.

The average separation between the proton and the electron in a hydrogen atom in the ground state is $5.3\times {10}^{-11} \mathrm{m}$. 

(a) Calculate the Coulomb's force between them at this separation.

(b) When the atom goes into its first excited state, the average separation between the proton and the electron increases to four times its value in the ground state. What is the Coulomb's force in this state?

The geostationary orbit of the Earth is at a distance of about $36000 \mathrm{km}$ from the Earth's surface. Find the weight of a $120 \mathrm{kg}$ equipment, placed in a geostationary satellite. The radius of the Earth is $6400 \mathrm{km}$.