Riemann's green is a green pigment ZnO.CoO, which is obtained by heating a mixture of zinc oxide and cobalt nitrate or by the reaction of cobalt nitrate with either or zinc sulphate.
1.ans: No the tension in the string of a simple pendulum is not constant throughout the motion
v is velocity of the bob and theta is the angle made by the string with vertical axis.as v and both are variable T is also variable.T is maximum at mean position as at mean position v is max and the angle is minimum.
2.ans: If the amplitude of the simple...
The two vectors (say A and B) of different magnitudes cannot be combined to give zero resultant since minimum value of combination is ІA-BІ which is not zero if AB.
The three vectors A, B and C of different magnitudes can be zero such that they form a closed triangle, then,
A+B+C=0
or, C=-(A+B)
Hence, the sum of three vectors may be zero if vector sum of any two vectors is equal and opposite to the third vector.
Note: The vectors can give this result only if...

very fine!
Glad to hear, miss!