Ron

In order to remove paint from our skin, why do we use turpentine? Why doesn't water remove the paint? I guess it has got something to do with miscibility/immiscibility of liquids but I don't know the exact reason. Thanks, Ron

But what are they capable of pulling? What do they pull? Ron

I came across the following paragraph on the working of muscles in a book: Muscles bring about movement by contracting (shortening) & relaxing (lengthening). One end of a muscle is attached to a movable bone where as the other end is attached to a fixed bone. When the muscle contracts, it pulls the movable bone. Since muscles are only capable of pulling, they work in pairs. Now what does the line in bold mean? Aren't muscles capable of pushing? Thanks, Ron

That is true but I would like to know the scientific reason why doesn't water (or the rope) travel forward with the wave. What exactly happens which gives the impression that water (or the rope) is moving forward where as they don't? Thanks, Ron

What is the place from where the leaf comes out of stem called? Is it the node? Also the roots which absorb water & minerals from the host plant are called what? Thanks, Ron

You have said that the wave itself travels forward but the wave is made up of water. So why is it that the water does not travel with the wave? Thanks, Ron

I came across a book which states the following about (sea) waves: Waves are the movements in the water body where water particles move up and down. It is important to note that water does not travel with the wave. Can someone please explain me what does the second sentence (in bold) mean? If water doesn't travel with the wave, how does the water move forward? The attached image also shows waves moving the water forward. It's really confusing.... Thanks, Ron waves.bmp

Can someone please tell me why do aircrafts have pressurized cabins? Has it got something to do with the difference between the low atmospheric pressure outside the aircrafts (since they fly at very high altitudes) & the pressure inside the aircraft? Also if the same force is applied for the same time to a car & a loaded truck, which of the two will pick up greater speed & why? Thanks, Ron

You mean to say that the natural gas is at such a high pressure that it forces petroleum to flow out? If that is the case, does that mean that the natural gas & petroleum come out simultaneously? You have also said that they don't wait for the natural gas to be released but in the book I am reading, it is stated that the natural gas comes out first with a great pressure. Thanks, Ron

OK....so is it like this? When natural gas gets released, the pressure decreases. At this point, the atmospheric pressure which is greater than the pressure above the layer of petroleum forces petroleum to flow out. Am I correct? Thanks, Ron

Thanks mate for your prompt reply but sorry to say I couldn't follow it. How will the pressure of the natural gas above the oil push the oil up even if all the natural gas would not have come out? Won't the whole of the natural gas come out first after which only the petroleum will flow out? Thanks, Ron

I have come across the following paragraph on drilling of oil wells in a book: Natural gas is found above petroleum, trapped between the rock cap and the petroleum layer. With the help of giant rigs, a hole is drilled in the earth's crust. When the hole reaches the rock cap, the natural gas comes out first with a great pressure. After that, petroleum starts flowing out due to the pressure of natural gas. When the pressure falls further, the petroleum is pumped out by electric motors. What does the line petroleum starts flowing out due to the pressure of natural gas mean here? After the natural gas comes out with great pressure, petroleum beneath the natural gas flows out but what does due to the pressure of natural gas mean here? Natural gas has already come out (after which petroleum starts flowing out); so how does pressure of natural gas come into the picture after the natural gas has already been released? Thanks, Ron

Please have a look at the attached image. What could be the reasons for the bulb not glowing? One reason is the use of a weak electrolyte.....what could be the other reasons? Thanks, Ron

Please have a look at the attached image. What could be the reasons for the bulb not glowing? One reason is the use of a weak electrolyte.....what could be the other reasons? Thanks, Ron

Air is a poor conductor of electricity but how does an electric current pass through air during lightning? Thanks, Ron

How does a liquid/medicine dropper suck in liquid? To some extent, I guess I know the answer but am not sure. When the bulb of the liquid dropper is squeezed, it forces out all the air from the dropper which creates a low air pressure inside the dropper. When the liquid dropper is immersed in the liquid & the bulb of the dropper is released, outside air pressure forces the liquid inside the liquid dropper but why does the outside air pressure force the liquid to go inside the dropper? Thanks, Ron

OK....here are my answers..... 1. Which force is responsible for raising our body hair when we try to take off a terylene or polyster shirt in dry weather condition? Frictional force but not sure 2. An object experiences a net non-zero force. Is it possible for the object to travel with a constant speed in a straight line? No. An object experiencing a net zero force will either be at rest or will be moving at a constant speed but an object experiencing a net non-zero force will have a changing speed. Am I correct? Assuming yes, how will an object move if the object is experiencing a net zero force? Can someone please correct me my wrong answers? Thanks, Ron

I have got some class VIII homework questions which I am not able to answer. Can someone please help me out with them? 1. Which force is responsible for raising our body hair when we try to take off a terylene or polyster shirt in dry weather condition? 2. An object experiences a net non-zero force. Is it possible for the object to travel with a constant speed in a straight line? 3. When we throw a ball upwards, what happens to its speed while it is going up? Give reasons for your answer. Fill in the blanks: 1. To draw water from a well, we have to _______ at the rope. Please note that all questions are from the lesson "Force & Pressure". Thanks, Ron