00:01
Question number 67, we know that if an object is placed on a fluid, then bind force acts on the object.
00:16
The bind force always acts in the upper direction and the weight of the object acts in the turnworld direction.
00:25
If the bind force becomes equal to the weight of the object, then the object starts floating and becomes in vertical equilibrium position.
00:35
Now, if the density of the object becomes equal to the density of the fluid, then the object remains at rest.
00:47
But if the density of the object becomes greater than the density of fluid, then the object starts sinking.
00:54
So we will use these concepts in solving this question.
00:59
For the first part of the question, it is said that there is a rock with mass of 0 .8.
01:10
And the density of the rock is equal to 3 ,300 kg per meter cube.
01:30
And it is given that the rock is placed in the water, the weight of the rock is acting downwards, and the bind force by the water is in the upwards direction, and since the rock is hanging by a string so string is pushing the rock is pulling the rock with the tension force t hence the tension force is acting on the rock by the string so for the equilibrium of the rock we can write the wind force plus the tension force by the string on the rock should be equal to the weight of the rock so the tension force t is equal to weight of the rock minus the bind force.
02:25
Now, substituting the formulas, the weight is mass of rock into exhalation due to gravity minus bind force has formed of density of water into g into volume of the rock.
02:39
Volume of the rock can also be written as the mass of the rock divided by the density of the rock.
02:49
So, substituting the values, the tension force, t, is equal to mass 0 .8 kg into 9 .8 this is the weight of rock minus density of water which is 1000 kg per meter cube acceleration due to gravity is 9 .8 into mass which is 0 .8 kg divided by density of rock density of rock is 3 ,300 kg per meter cube so solving this, we will get the required tension force 5 .46 newton.
03:44
This is our answer for part a.
03:50
Now for part b, for part b, it is given that if the tension force increases by 12%, that is the new tension force becomes 1 .12 of the initial tension force...