IIT JEE Main 2017 Physics Question 1 Set A

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 = 93
and Final area / Initial area = 92
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 = (93/92)=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.

IIT JEE Main 2016 Maths Question 38

IIT JEE Main 2016 Maths Question 38: 

The eccentricity of the hyperbola whose length of the latus rectum is equal to 8 and the length of its conjugate axis is equal to half of the distance between its foci, is:

(1) 2/√3
(2) √3
(3) 4/3
(4) 4/√3

Solution

Given in problem statement that for the hyperbola whose length of the latus rectum is equal to 8, i.e.
2b2/a=8
& the length of its conjugate axis is equal to half of the distance between its foci, hence, 2b =ae
=> 4b2 = a2e2
=> 4a2 (e2 -1) = a2e2
=> e = 2/√3

Answer to IIT JEE Main 2016 Maths Question 38

Correct answer to given problem No 38 of IIT JEE Main Maths paper of 2016 is option number (1) that is the eccentricity of hyperbola is 2/√3.