A1.0-kg weight is suspended from the middle of a 1.3-m long rope that has one end fixed to a wall. what force would you have to exert on the other end of the rope to pull it perfectly horizontal?

a. 49 n
b. 0.98n
c. 980n
d. 0.49n

e. it cannot be done

e. It cannot be done

Explanation:

Let  T be tension in the rope. The component of T in vertical direction will balance the weight .

Since T makes angle 90 degree with vertical ( since rope is perfectly horizontal )

2T cos 90 = mg

T = mg / 2 cos 90

= mg / 2 x 0

= infinity

Tension will have to be infinity which is not possible .

e/c, where e is its total energy

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