Question

l. A rock is suspended from a string and moves downward at constant speed. Which statement is true
concerning the tension in the string if air resistance is ignored?
(a) The tension is zero newtons.
(b) The tension points downward.
(c) The tension is equal to the weight of the rock
(d) The tension is less than the weight of the rock.
(e) The tension is greater than the weight of the rock,​

Answer 1

Tension is Less Than The Weight Of The Mass.

EINSTEINS RELATIVITY TELLS,

With respect to any non accelerating reference frame, accelerating frames has gravity..concluding gravity and acceleration are same.

Here in the case,

acceleration and g are in same direction resultant will be the difference b/w them..

Here thus Relative acceleration is reduced.

Thus the Rope holding the block too feels less tension.

Answer 2

Answer:

The true statement is option (d) The tension is less than the weight of the rock.

Step-by-step Explanation:

A rock is suspended from a string and moves downward at constant speed. So, there is no external acceleration happens. Only gravitational acceleration takes place.

The formula for tension is given by,

$t = m \times g$

If the body moves upwards,

$t = w + ma$

If the body moves downwards,

$t = w - ma$

'm' is the mass of the rock.

'g' is the acceleration due to gravity.

If there is a presence of air resistance, the formula is given by,

$t + r = mg$

where, 'r' is the resistance in air.

The above equation can be return as,

$t = mg - r$

We know that,

$w = mg$

Hence, the tension is given as,

$t = w - r$

If the air resistance is ignored, then r = 0,

So that,

$t < w$

Due to downward gravitational force and the absence of air resistance,the tension of the rock is less than the weight of the rock.

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