Rank the tensions

F=25a. F-T3=2a then T3=23a. T3-T2=8a then T2=15a. T2-T1=5a then T1=10a. So T3>T2>T1.

This question ask only qualitatively about the comparison for the tension in different cords.

All the blocks are tied together and hence they move with same acceleration towards right.

Cord 1 pulls 10kg only , Cord 2 pulls 15 kg, cord 3 is pulling 23 kg .. Therefore tension in cord 3 is max and cord 1 is minimum.

Cord 3 was 2 kg pulling 23 kg. 21 N tension.

Cord 2 was 10 kg pulling 15. 5 N tension.

Cord 1 was 15 kg pulling 10. -5 N tension.

speaking logically without numbers ... since the three cords stiff enough and the force "F" is constant then the whole system moves with constant acceleration "a" , now cord1 need to pull less mass than other cords with that acceleration and cord2 needs to pull more mass than cord1 and less mass than cord3 , the same for cord3 , so tension exerted in cord3 must be the largest and tension in cord1 must be the smallest , that is to say , cord 3 > cord 2 > cord 1

Drawing free body diagrams, you can see that its 3,2,1.

We actually don't need values for the masses of the blocks to solve this problem. Let's say the block furthest on the left is mass x, the next is mass y and the next is mass z. If we look at cord 1, the mass it by itself is pulling is equal to x. Cord 2 is pulling mass x and mass y. Cord 3 is pulling mass x, mass y and mass z. x + y + z > x + y > x. Force is equal to mass times acceleration, and since each block is connected by cords each mass has the same acceleration. Therefore, the only determining factor in amount of force is the mass each cord is pulling. Since we already determined the mass in order from largest to smallest, we can answer the question with certainty. The answer is A, cord 3 > cord 2 > cord 1.

An important thing to remember for these "order" questions is that rarely do we need actual values in order to determine the answer. Knowing that mass is an intrinsic property of matter and is always a scalar, when variables are used to represent the masses two variables added together are always bigger that one of those variables and always smaller than those two variables plus another variable.

I assumed the cords have equal tensility and inferred that the simultaneous inertial force acting on each of them accumulates from left to right.