IIT JEE Main 2017 Physics Question 1 Set A:

A man grows into a giant such that his linear dimensions increase by a factor of 9. Assuming that his density remains same, the stress in the leg will change by a factor of:

(1) 9 |

(2) 1/9 |

(3) 81 |

(4) 1/81 |

#### Solution

Given in problem that the linear dimensions increase by a factor of 9 that is the length, width and height get multiplied by 9. However, it is also given that the densities remain the same.

thus, Final density = initial density

=> Final mass / Initial Mass = Final Volume / Initial Volume

=> Final mass / Initial Mass = 9^{3}

and Final area / Initial area = 9^{2}

As stress = force / area = Mass x g / area

hence Final stress/ Initial Stress = (Final Mass x g/ Final Area )(Initial Area/ (Initial Mass x g))

=> Final Stress / Initial Stress = (9^{3}/9^{2})=9

#### Answer to IIT JEE Main 2017 Physics Question 1 Set A

Correct answer to given problem No 1 of IIT JEE Main Physics paper of 2017 Set A is option number (1) that is the stress in the leg will change by a factor of 9.