During the British period newspapers also acted as source of social reformation​

Answer:

The solution composition can be described in mass percentage which shows the mass of solute present in a given mass of solution. The quantity of solute is expressed in mass or by moles. For a solution, the mass per cent is described as the grams of solute per grams of solution, multiplied by 100 to get the percentage.

Answer:

Mass percentage of solution is defined as the mass of the solute in grams dissolved per 100 g of the solution.

Answer:

36 → 23 +13

30 → 17 + 13

45 → 2+ 43

Answer:

The law of multiple proportions states that if two elements form more than one compound between them, the masses of one element combined with a fixed mass of the second element form in ratios of small integers.

Explanation:

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Answer:

technology is defined as a study of new techniques of producing machines..

Explanation:

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Explanation:

From the top of a multi- storeyed building, 39.2m tall, a boy projects a stone vertically upwards with an initial velocity of 9.8ms−1 such that it finally drops to the ground. (i) When will the stone reach the ground? (ii) When will it pass through the point of projection? (iii) What will it pass through the point of projection? (iii) What will be its velocity before striking the ground? Take g=9.8ms−2.

Answer

Hint:Use the equations of motion formula and calculate the height of projection from the building and the time taken by the stone to reach the ground. Divide the time taken to reach the ground by two, to find the time taken to reach the point of projection. Use the equation of motion again to find the final velocity of the stone.

Useful formula:

(1) The equation of the motion is given as

v2=u2−2gs

Where v is the final velocity, u is the initial velocity, s is the distance covered and g is the acceleration due to gravity.

(2) The other equation of motion is given as

V=u+gt

Where V is the final velocity of stone.

(3) The third equation of motion is given as

S=ut+12gt2

Complete step by step solution:

It is given that the

Height of the multi- storeyed building, h=39.2m

Initial velocity of the stone, u=9.8ms−1

(i) Using the equation of motion,

v2=u2−2gs

Substitute the value of the given initial velocity, final velocity as zero and the acceleration due to gravity in above equation.

02=9.82−2×9.8s

By simplifying the above equation, we get

s=4.9m

The height of the stone from the ground 4.9+39.2=44.1m

V=u+gt

V=0+9.8×1

By simplification of the above step,

V=9.8ms−1

Using the third equation of motion,

S=ut+12gt2

Substituting all the parameters we get

39.2=9.8t+0.5×9.8t2

By doing various mathematical operations, we get

(t+4)(t−2)=0

The time taken is taken as 2 , since it is positive. And hence the total time to reach the ground is 2+2=4s .

(ii) The time taken to pass the point of projection is obtained by dividing the total time by

2 , 42=2s .

(iii) Using the first equation of motion,

V2=U2+2gs

Substituting the known parameters in it,

V2=9.82+2×9.8×39.2

By performing the basic arithmetic operations, we get

V=96.04+768.32−−−−−−−−−−−−√

By simplifying further, we get

V=29.4ms−1 .

Hence the velocity of the stone before striking the ground is 29.4ms−1 .

Note:At first equation of the motion, the final velocity is substituted as zero. This is because the stone reaches the at most point at that time the velocity of stone decreases to zero. While falling down, the stone moves with the acceleration due to gravity.