a rock suspended from a string moves downwards at constant a=g. Which of the following is true concerning the tension in the string?
a) the tension is zero
b)the tension is equal to the weight of the rock
c)the tension is less to the weight of the rock
d)the tension is greater to the weight of the rock
wouldn't the amswer be a)?
Yes, the rock is weighless
No, the answer is actually d) the tension is greater than the weight of the rock.
To understand why, let's consider the motion of the rock. The rock is moving downwards, which means there must be a net force acting on it. In this case, the only force acting on the rock is its weight (W = mg), where m is the mass of the rock and g is the acceleration due to gravity.
Since the rock is accelerating downwards with a constant acceleration of g, we know that there must be an additional force acting on it in the same direction. This additional force is provided by the tension in the string.
So, if we compare the tension in the string to the weight of the rock, we can conclude that the tension must be greater than the weight. Mathematically, we can express this as T > W, where T represents the tension and W represents the weight of the rock.
Therefore, the correct answer is d) the tension is greater than the weight of the rock.