PRESSURE
- Explain why divers mustbreathe out as they rise to the surface?
[Show answer]As the diver ascends from the bottom to the surface, the pressure exerted by water decreases. This decrease in pressure causes the volume of any gas in the diver’s lungs to increase if the diver does not compensate.
- Why is the atmospheric
pressure less at the top of a mountain than it is at the bottom of the mountain?
[Show answer]This is because the Atmospheric pressure decreases with the increase of altitude since the weight of atmosphere decreases. At the top of a mountain the weight of the atmosphere is low hence low atmospheric pressure.
- Use your knowledge of
pressure to explain why the pressure increases as you dive towards the bottom of the swimming pool
[Show answer]The pressure in liquids depends on depth. When you dive towards the bottom of swimming pool the weight of water acting on you increases hence the pressure increases.
- Why do people suffer from nose bleeding at high altitudes?
[Show answer]Nose bleeding is a result of blood pressure being high than the atmospheric pressure. As a person rises to high altitude, the weight of the atmosphere above him/her decreases and so the atmospheric pressure falls.
As the atmospheric pressure falls, the body’s blood pressure stays the same. This makes the inside pressure (blood pressure) higher than the outside (atmospheric) pressure. As a consequence, blood pushes harder on the blood vessels and may cause veins to rapture at places where they are weak/thin such as in the nose, thereby resulting to NOSE BLEEDING. - Why it is easier to cut a piece of meat using a sharp knife than a blunt knife?
[Show answer]A ship knife has a smaller cutting edge than a blunt cutting edge. Under the application of the same force, a sharp knife will thus exert more pressure than a blunt one.
- Why the bottom of the dam in made thicker than the top?
[Show answer]This is because liquid pressure increases with depth, so the pressure at the bottom of the dam is much greater than that at the top; hence the bottom of the dam has to be much stronger than the top.
- Why the atmospheric pressure at sea level different from that on top of Mount Kilimanjaro?
[Show answer]This is because the Atmospheric pressure decreases with the increase of altitude since the weight of atmosphere decreases. At the sea level there is high atmospheric pressure while on top of Mount Kilimanjaro atmospheric pressure is high
- Why the tyres of a tractor are large and wide?
- Why a woman wearing shoes with pointed heels is more likely to cause damage to a wooden floor than an elephant?
[Show answer]This is because the shoes with the pointed heels have small area of contact with the floor hence resulting high pressure while the elephant exerts low pressure to the floor due to have large area of the contact with the floor.
- Explain why pressure of atmosphere does not break windows?
[Show answer]Because atmospheric Pressure is exerted on both sides of a window, so no net force is exerted on the window and hence uniform pressure does not break the window.
- Use a diagram to describe how manometer can be used to measure the pressure of a gas at a gas-tap.
[Show answer]Manometer is a U-shaped device used to measure gas pressure. When both ends are open, the pressure on both sides are equal.
When one end is connected to unknown pressure P1 the liquid level falls in the one arm and rises on the other arm.
P1 is greater than P2P1 = P2 + ∆h𝞺gThe change in height is because of change of pressure. - Explain why hitting an inflated balloon with hammer will not cause it to burst but sticking it with a pin will.
[Show answer]Hitting an inflated balloon with a hummer will not cause it to burst because the force is distributed over a larger surface area, reducing the pressure exerted on the balloon while sticking an inflated balloon with a pin concentrates the force onto a very small surface area creating high pressure causing it to burst.
- During MASHUJAA MEMORIAL CEREMONY, Brigadier Chacha climbed Kilimanjaro Mountain Peak. Explain variation of atmospheric pressure experience as he climbs up the mountain peak.
[Show answer]As Brigadier Chacha climbs Kilimanjaro Mountain peak, he will experience variation in atmospheric pressure due to change of altitude. The atmospheric pressure decreases with increase of altitude. This decrease of atmospheric pressure is noticeable by physiological effect such as decrease of oxygen availability that can lead to sickness.
- Describe carefully how you would use a siphon to remove a major part of the water contained in a large, fixed tank, open at the top. Draw a diagram and use it to explain the action of the siphon.
[Show answer]EXPLANATION
Water rises in the tube because it is pushed by atmospheric pressure. The force of gravity draws water through the long arm and this maintains the low pressure that is established at the short arm. Once start, the siphon does not require addition energy to maintain water flowing out of the tank. The siphon will pull out large part of the water in a large fixed tank.
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