V K Sally and R Goel Solutions for Chapter: Gravitation, Exercise 9: Practice Problems

An object has a mass of $30 \mathrm{kg}$. What is its weight,

(i) on the Moon,

(ii) on another planet?
The value of ‘g’ on the Moon is ${\frac{1}{6}}^{\mathrm{th}}$ that of the earth and $3$ times that of the earth on the planet. $[g_{earth}=10 \mathrm{m}/{\mathrm{s}}^2]$ 
 

A person of mass $70 \mathrm{kg}$ weighs himself on a weighing machine, first on the earth and then on a planet where acceleration due to gravity is $\frac{1}{2}$ that on the earth. Calculate the reading of weight on the weighing machine, ${\mathrm{g}}_{\mathrm{earth}}= 9.8 \mathrm{m}/{\mathrm{s}}^2.$

A stone thrown vertically upward rises to a height of $29.34 \mathrm{m}$ on the surface of the moon. If the acceleration due to gravity on the surface of the moon is $1.63 \mathrm{m} {\mathrm{s}}^{-2}$. Calculate the initial velocity of the stone. 

A stone thrown vertically upward rises to a height of $29.34 \mathrm{m}$ on the surface of the moon. If the acceleration due to gravity on the surface of the moon is $1.63 \mathrm{m} {\mathrm{s}}^{-2}$. Calculate the time taken to gain the maximum height.
 

A ball thrown vertically upward rises to a height of $20 \mathrm{m}$. If the acceleration due to gravity is $10 \mathrm{m} {\mathrm{s}}^{-2}$. Calculate the initial velocity of the ball. (Take $g=10 \mathrm{m} {\mathrm{s}}^{-2}$)

A ball thrown vertically upward rises to a height of $20 \mathrm{m}$. If the acceleration due to gravity is $10 \mathrm{m} {\mathrm{s}}^{-2}$. Calculate the time taken to gain the maximum height.