Important Questions for Class 8 Chapter 11 - Force and Pressure

Important questions based on NCERT syllabus for Chapter 11 - Force and Pressure:

Question-1: What is a cyclone? What is the reason for the formation of cyclones?

Solution: Cyclone refers to any spinning storm that rotates around a low-pressure center. The low-pressure center is also referred to as the 'eye' of the storm, which is well known for being eerily calm compared with the areas under the spinning 'arms' of the storm. Cyclones are basically created by the differences in air pressure. A cyclone is formed when a system of winds moving in circular motion closes in toward an area of the sea with low atmospheric pressure.

Question-2: Explain the following :

Solution: A. Why does a helium balloon burst when it rises too high up?
B. Why do we feel nauseated when we go deep into the water?

A. Pressure decreases as we go up in the atmosphere so when the helium balloon rises up the pressure inside the balloon becomes more than the pressure outside and so the balloon first expand and then finally bursts.

B. As we go deep into the water the pressure increases. So now there is higher pressure outside and less pressure inside the body. So our lungs feel crushed and we feel nauseated.

Question-3: Why is it difficult to pull out a rubber sucker stuck to surface like glass?

Solution: When you press the rubber sucker on a surface, most of the air between it and the surface escapes out. The sucker sticks to the surface because the pressure of atmosphere acts on it. To pull the sucker off the surface, the applied force should be large enough to overcome the atmospheric pressure. And that force is quite large. And that’s why it’s hard to pull off the rubber sucker from a surface.