Birds are often seen to swell their feathers in winters. Why?

Q: Why does the bottom of a tire pump feel hot when you pump air in the tire, but when air is released,…

A: Given:  A pump which is used to pump air into a tire.

Q: For divers going to great depths, the composition of the air in the tank must be modified. The ideal…

A:

Q: Why is it easier to start fire with kindling rather than with large match sticks and logs of same…

A: Kindling has greater surface area per unit mass as compared to large sticks and logs. Hence, it…

Q: Is it a cause of worry when your body temperature is 310K?

A: The average body temperature of human being ranges from 36.5°C to 37.5°C. Any temperature below 35°C…

Q: Particles of camphor move around on the surface of water. Why?

A: The surface tension of water decreases when the impurities are dissolved in it. The camphor is…

Q: How is the energy value of foods determined?

A: The amount heat released  by burning these substances (food) in a calorie-meter is the energy of…

Q: What is effect of temperature on elasticity?

A: The modulus of elasticity is a characteristic property of a given material and it is a measure of…

Q: A typical timber wolf has a mass of 40 kg, a typical jackrabbit a mass of 2.5 kg. Given the scaling…

A:

Q: 2. Determine an equation to predict metabolism rate as a function of mass based on the following…

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Q: Why do thin french fries cook faster than thick fries?

A: Surface area of small object is large, so the smaller the object the larger the surface area.

Q: What is the difference between an adiabatic wall and a diathermic wall?

A: Difference between an adiabatic wall and a diathermic wall is:

Q: Why do Eskimos build double walled houses of blocks of ice?

A: The Eskimos build double walled houses in order to keep the interior of their houses warm.

Q: Objects deep beneath the surface of the ocean are subjected to extremely high pressures. Some…

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Q: Mosses don’t spread by dispersing seeds; they disperse tiny spores. The spores are so small that…

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Q: Why do some animals curl up into a ball when they are cold?

A: By Stefan's law of energy radiation, rate of radiation of energy is directly proportional to surface…

Q: Which is heavier 1kg of nail or 1kg of cotton? Why?

A: nail is heavier in case of presence of air, in vacuum both are same.

Q: Why do substances expand when temperature is increased?

A:

Q: By how much does a 20 m steel girder on a bridge expand or shrink from an average -7o C winter to an…

A: The change in the steel girder’s length can be determined as, Here, α, L0, and ΔT represents the…

Q: What is the reason why Ice with salt melts faster than Ice only?

A: Given : Ice with salt melts faster than Ice only.

Q: Tents are coated with thin layer of aluminium hydroxide. Why?

A: Tents are coated with a thin layer of aluminium hydroxide because aluminium hydroxide is insoluble…

Q: Who has more need for drink in a dry desert climate, a child or an adult?

A: The rate at which dissipates heat from an object is directly proportional to the surface area.…

Q: How did cavemen keep warm?

A: Archaic humans had much of body hair (fur) to keep them warm from cold, and protect from sun.…

Q: why does long trail is usually less elastic than short trails?

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Q: Does water boil at higher temperatures at higher pressures? Explain.

A: Water boil at higher temperatures at higher pressures

Q: Birds swell their feather in winter, Why?

A: Birds often swell their feathers in the winter in order to keep themselves warm.

Q: Ice covered with a gunnu bag does not melt for long time. Why?

A: The air is a good insulator of heat. In gunny bags, there are pores between consecutive layers or…

Q: Cooking utensils are provided with wooden handles, Why?

A: Wood is a very poor conductor of heat energy, means that heat energy from cooking pan cannot…

Q: What is Insulation ?

A: Insulation is used to fill the spaces such as little gaps behind walls and above ceiling of the home…

Q: Is the stickiness of oranges in our hands can be easily washed with tap water?

A:

Q: What happens when the stretching force on an elastic material is released?

A: An elastic material can return to it's original shape after being stretched or compressed. This…

Q: A 10-cm-thick wall is to be constructed with 2.5-m-long wood studs (k = 0.11 W/m·K) that have a…

A: Given data The thickness of the wall is: tss = 10 cm = 0.1 m The length of the initial stud is: li-s…

Q: When you exhale outdoors on a cold day, you can “see your breath.” Why?

A: When a person exhales, it containes water vapor. When it comes in contact with cold air, it forms…

Q: What happens to the volume of water when it freezes?

A: Freezing point depression refers to the lowering of the freezing point of solvents upon the addition…

Q: Differentiate between Stretching and Compressing of materials?

A: Stretching : Stretching means pulling of an object. In physics, stretching refers to pulling of an…

Q: If you add salt continuously to a glass of water, eventually some salt will remain at the bottom.…

A: Given Assertion: If we add salt continuously to a glass of water, eventually some salt will remain…

Q: Oil rises in lamp wick, Why?

A: The oil in the wick of an oil lamp rises up due to capillary action. This effect is due to surface…

Q: Calculate the depth (in km) to which Avogadro's number of table tennis balls would cover the Sun.…

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Newton's First Law of Motion

If a very smooth ball is rolled down an inclined surface with zero friction, the ball will continue to roll indefinitely for an infinite time, in an attempt to reach to the same height on the opposite hill!