Two blocks attached by a string(dynamic)

[MikeMai]

1. Homework Statement
Two blocks (m1=4.0kg, m2=7.5kg) are attached by a light cord pulled along a horizontal surface by a force of 53N as shown in the diagram. If the coefficient of friction between the blocks and the surface is 0.30, what is the tension in the rope between the two blocks.

M2 -------- M1 ------->Force applied


2. Homework Equations
Fnet= Ma


3. The Attempt at a Solution

I used the Fnet=ma, on m1 i got Fapplied - T - Ff = ma
But i don't know how to find the acceleration. And i know there's two different frictions because of two different mass. So i don't know how to join them together and find Tension.

ps: I just joined this forum, What should i do if i have a a lot of questions or simply want someone to check over my assignment for me before I hand them in? (got like 20-30questions). I don't want to violate the rule so I am just wondering if there's a specific section to post or something.

 

[ap123]

What about M2?
Apply Newton2 to M2 and then you'll have 2 equations to work with.

If you have other questions you want to post, then create a new thread for each one.

 

[MikeMai]

Hmm, ok so now i got this.

m1:
Fnet=m1a
Fapplied-T-Ff=m1a

m2:
Fnet=m2a
T-Ff=m2a
a=T-Ff/m2

plug a into m1's equation

Fapplied-T-Ff=m1(T0Ff/m2)
53-T-(0.30x4.0x9.8)=4.0(T-0.30x7.5x9.8/7.5)
53=1.53T
T=34.565N = 35N

If someone can check if i did the calculation right, it would be greatly appreciated.

Thank you.

 

[ap123]

Yes, this is correct :)

 

[Nickie]

I would suggest starting by drawing a free-body diagram for each block and labeling all the forces acting on them. This will help you visualize the problem and identify any missing information.

To find the acceleration, you can use the fact that the two blocks are connected by a string, so they will have the same acceleration. You can also use the fact that the net force on the system (both blocks) is equal to the force applied, which is 53N in this case.

To find the tension in the rope, you can use the equations you have already set up for each block and solve for the tension. Remember to consider the direction of the tension in each equation.

If you have multiple questions or want someone to check your assignment, I would suggest posting them in the appropriate section of the forum, such as the Homework & Coursework Questions section. Be sure to follow the guidelines and provide all the necessary information for others to help you effectively. Good luck!