I have the solutions to Ch. 5 Question 9 for A,B,C,D, and E, I have posted a pho
ID: 2120441 • Letter: I
Question
I have the solutions to Ch. 5 Question 9 for A,B,C,D, and E, I have posted a photo of Ch 5 Problem 9 at the bottem of this post. Can some one answer the following:
1)From the previous problem, Chapter 5, Question 9, obtain the magnitude of the force F and tensions on those cords, when the boxes are moving with a velocity of 10 m/s.
2)From the previous problem, Chapter 5, Question 9, the boxes are on a floor with friction now. When the force of 30 N is applied, the boxes are moving with acceleration of 1.3 m/s2.
Explanation / Answer
1) ANSWER TO THE 1st PART
Since the blocks are moving with a constant velocity of 10 m/s and not any acceleration, we can easily say that all the forces on each block are balanced.
Drawing the F.B.D of each block we can see that the Tensions in each cord are same and equal to the applied Force
So the magnitude of F and the Tensions are absolutely same. But we can not determine any certain value for both.
What we can say is that whatever the value of F is, if it falls under the tensile strength of the cords, same is the value of Tension in the cords.
2) ANSWER TO THE 2nd PART
F= 30 N (given)
2 kg block : 30-T3-(mu)*2*g = 2* 1.3
5 kg block : T3-T2-(mu)*5*g= 5*1.3
3 kg block : T2-T1-(mu)*3*g = 3*1.3
10 kg block : T1- (mu)*10*g= 10*1.3
Adding all the above equations :
30- (mu)*20*g = 20*1.3
(mu) = (30 - 26)/20*g = 4/196 = 0.0204
Now putting this value in the last equation..(0.0204*g = 0.2)
T1 = 13 + 2 = 15 N
T2= 3.9 + 15 + 0.6 = 19.5N
T3 = 6.5 + 19.5 + 1 = 27 N