Advertisements
Advertisements
Question
If someone presses a pointed needle against your skin, you are hurt. But if someone presses a rod against your skin with the same force, you easily tolerate. Explain.
Advertisements
Solution
We know that pressure is the application of force over a particular area. In mathematical terms, pressure is equal to force divided by area; that is, with more force comes more pressure and with more area comes less pressure. An iron rod has more surface area than the pointed tip of a needle. That is why the pointed needle exerts more pressure than the iron rod (with the same force) when pressed against our skin.
APPEARS IN
RELATED QUESTIONS
Toricelli’s barometer used mercury. Pascal duplicated it using French wine of density 984 kg m–3. Determine the height of the wine column for normal atmospheric pressure.
A man exerts same pressure on the ground whether he is standing or he is lying.
Pressure is the thrust acting on a surface of ........... area.
Name two factors on which the pressure on a surface depends.
It is easier to cut with a sharp knife than with a blunt one. Explain.
Calculate the pressure in pascal exerted by a force of 300 N acting normally on an area of 30 cm2.
How much thrust will be required to exert a pressure of 20,000 Pa on an area of 1 cm2.
A beaker containing a liquid is kept inside a big closed jar. If the air inside the jar is continuously pumped out, the pressure in the liquid near the bottom of the liquid will
Consider the situation of the previous problem. Let the water push the left wall by a force F1 and the right wall by a force F2.
In a hydraulic lift, the input piston had surface area 30 cm2 and the output piston has surface area of 1500 cm2. If a force of 25 N is applied to the input piston, calculate weight/force on output piston.
A chapatti maker is a machine which converts balls of dough into chapatties. What effect of force comes into play in this process?
If the same force is made to act on a larger area, the pressure ______.
What is thrust?
Why dams are made stronger and thicker at the bottom than at the top?
Give reasons why:
heavy trucks are fitted with 6 to 8 wheels
Scuba divers wear special suits to withstand ______.
The shape and size of the solids do not easily change.
Upthrust = weight of the fluid displaced – apparent weight of the object.
A vessel filled with water is kept on a weighing pan and the scale adjusted to zero. A block of mass M and density ρ is suspended by a massless spring of spring constant k. This block is submerged inside into the water in the vessel. What is the reading of the scale?
