Why in hand driven grinding machine, handle is put near the circumference of the stone or wheel ?

In a wheel and axle machine the radii of the wheel and axle are 0.5 m and 0.05 m,respectively . A weight of 100 kg is raised when it is hanging by a rope from the axle by applying a force of 12 kg on the circumference of the wheel . Find the mechanical advantage, velocity ratio and efficiency of this machine.

Why are doors provided with handles near the outer edges, far away from the hinges ?

Take a piece of thread. Tie a small piece of stone to one end of the thread. Hold the other end of the thread in hand and whirl it round. Note the motion of the stone. If the thread breakes suddenly, the stone files off along tangent to the circle at the instant. Read the above passage and answer the following question: (i) which force is whirling the stone ? who is providing this force ? (ii) why does the stone fly off along the tangnet to the circle at that instant? (iii) what value of life do you learn from this?

The crowd surged forward through the narrow streets of Paris. There was a clatter of shutters being closed hastily by trembling hands-the citizens of Paris knew that once the fury of the people was excited there was no telling what they might do. They came to an old house which had a workshop on the ground floor. A head popped out of the door to see what it was all about "Get him! Get Thimonierl Smash his devilish machines!" yelled the crowd. They found the workshop without its owner. M. Thimonier had escaped by the back door. Now the fury of the demonstrators turned against the machines that were standing in the shop, ready to be delivered to buyers. They were systematically broken up and destroyed - dozens of them. Only when the last wheel and spindle had been trampled under foot did the infurtated crowd recover their senses. "That is the end of M'sieur Thimonter and his sewing machines," they said to one another and went home satisfied. Perhaps now they would find work, for they were all unemployed tailors and seamstresses who believed that their livelihood was threatened by that new Invention. The people thought that