Give reason. Why?
1.It is easy to hammer a pointed nail then a blunt one.
2.Canals can easily work on sand.
3.Coolies can be seen carring loads on tgeir head easily.
4.Ball keeps rolling on glass but stops on a cemented floor.
Answers
•It is easier to hammer a sharp nail than a blunt one into the wood. This is because blunt nail occupies more area than sharped nail. As pressure exerted it inversely proportional to area lesser the the area, the pressure will be more.So the sharp will exert more pressure as it occupies less area
•Canal lining is the process of reducing seepage loss of irrigation water by adding an impermeable layer to the edges of the trench. ... Lining a canal can also prevent waterlogging around low-lying areas of the canal. By making a canal less permeable, the water velocity increases resulting in a greater overall discharge.
•Porters place a round piece of cloth on their head when they carry heavy lods as the round piece of cloth increases the area on which the load is placed. We know that when surface is more than pressure is less. As a result, the pressure on their heads get reduced.
2.Canal lining is the process of reducing seepage loss of irrigation water by adding an impermeable layer to the edges of the trench. Seepage can result in losses of 30 to 50 percent of irrigation water from canals, so adding lining can make irrigation systems more efficient.
3.when the worker carrying a luggage on his head or on his hand then no work is done.
It has two causes,
As you know W=F⃗ ⋅S⃗ W=F→⋅S→,so here there is no displacement,hence no work done.
According to work energy theorem work done is equal to change in kinetic energy.But here no change in kinetic energy. So work done is zero.
4.Galileo Galilee once did an experiment by rolling different weighted balls down an inclined plane and proved that objects fall at the same speed no matter what they weigh. I explored further into this principle by rolling a ball down an inclined plane covered with different textures to see if texture affects the distance traveled by an object.
My hypotheses were supported by Newton’s Second Law, which states if a moving object is acted upon by a force it will change its speed in proportion