Question

All answers please!!​

Answer 1

Answer: KE = 1/2 mv^2

                 M = 100g = 0.1 kg

                  v = 180km/hr = 50m/s

                 ke = 1/2 x 0.1 x 50 x 50

                 ke = 125J

B) Refractive index is defined as

The ratio of the speed of light in a vacuum to its speed in a specific medium.

Refractive Index=

n = c/v

since Refractive Index is a ratio, hence it is a unitless quantity.

C) Pressure = Force/Area

i) pressure is directly proportional to for, if the force increases the pressure also increases and vice versa.

ii) Pressure is inversely proportional to surface area. hence when surface area increases pressure decreases.

D) Heat : It refers to the amount of energy present in a body.

It is measured in Joules.

Temperature : It is the measure of the heat’s intensity.

measured in Celsius, Fahrenheit, Kelvin

Answer 2

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A) Kinetic energy of a body is defined as the energy possessed by it due to it's motion. Mathematically it is defined as half of product of mass and square of velocity of a body.

$ke = \frac{1}{2} \times m {v}^{2}$

We have been given that :-

• Mass of body = 100g = 0.1kg.
• Velocity of body = 180km/h = 180 × 5/18 = 50m /s
• Kinetic energy = ?

After inputting the known values in the expression we get :-

$ke = \frac{1}{2} \times 0.1 \times {50}^{2}$

$ke = \frac{1}{2} \times 0.1 \times 50\times 50$

$ke = 0.1 \times 25 \times 50$

$ke = 125j$

Therefore the kinetic energy of body is 125J.

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B) Refractive index of a medium is the ratio of speed of light in air or vaccum to speed of light in given medium. It is represented by Greek letter

$\mu$. Refractive index have no unit because SI unit of both quantities in the ratio cancel out each other.

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C) Pressure is defined as the force applied per unit area on an object. Pressure is inversely proportional to area on which force is applied, and pressure is directly proportional to force which is applied on the area.

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D) Heat is measure of total energy of molecules.

Temperature is the average of total energy in molecules.

Heat is measured in Joules.

Temperature is measured in Kelvin.

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E - i) An air craft flying in the sky is at some height from earth's surface,thus it possess Potential energy and since it is in motion thus it also possess kinetic energy.

ii) The monkey sitting on top of a tree is at some height from earth's surface thus it possesses Potential energy and since it is not moving thus it possess no kinetic energy , but only potential energy.

iii) A compressed string posses potential energy which further converts to kinetic energy.

iv) Since bullet is fired thus it will have some motion and hence it will possess kinetic energy.

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BY SCIVIBHANSHU

THANK YOU

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