Question No. 1:
Look at the schematic figure below:
Here, a is the volume of the small stone and A is the surface area of the base of the wooden block
Balancing the buoyant force we get:
In this case we can write the equation as:
Thus, the submerged percentage of the wooden block is less than 50% in this case.
Question No. 2:
When the spring is not stretched, then the distance between the lower end of the spring and the floor is equal to the length of the bar.
Now, we will find the force applied by the bar at the lower end of the spring. That force will be equal and opposite to the “restoring force” of the spring on the bar. The free-body diagram of the bar is given below.
In state of equilibrium, the sum of torques about point O will be zero. Plus we are ignoring the friction of floor and the wall.
Question No. 3:
In this case first we will find the resultant of Fm and w.
X components are:
Question No. 4:
Height of tank is 50m & the height of the small hole is 2m.
Question No. 5:
The force applied by the wind is given as following formula:
Question No. 6:
Question No. 7:
Question No. 8: