Tension/pulley problem, Newtons second law

In summary,Two objects, A and B, are connected by an ideal string with masses of m1=1.00kg and m2=2.00kg respectively. Object A is moving with no friction on an incline, while object B is moving vertically. A force F with a magnitude of 6.00N is applied to object B causing it to accelerate downwards with a magnitude of 5.50 m/s^2. The free body diagrams for each object were created and Newton's second law was applied in the x-direction of object A and in the y-direction of object B. By solving for the tension force, it was found that T=20.6N.
  • #1
eventob
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Homework Statement


Two objects A and B, with masses m1=1.00kg and m2=2.00kg, are connected with an ideal string. Object A is moving on an ideal incline with 0 friction. Object B is moving vertically. A force F is working on object B. Its magnitude is 6.00N. Object b is accelerating downward, with a magnitude og 5.50 m/s^2.

a) Draw a free body diagram for the two objects
b) Find the tension force between the objects
c) Find the angle beta


Homework Equations


Newtons second law


The Attempt at a Solution


Made a free body diagram for each object. Then applied Newtons second law in the x-direction of object A and in the y-direction og object B.
A:
sigma F_x=F-T-m1*sin(beta)=m1*a
sigma F_y=n-m1*g*cos(beta)
B:
sigma F_y=f+T-m2*g=ma

Solved this for the variable T, and ended up with t=20.6 N. Obviously I am doing something wrong here, because when I try to find the angle beta, I end up with cos(beta)>1.

I am not sure whether the force F should be in the free body diagram og object A at all.

Thanks in advance.
 
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Forgot to upload this earlier. :)
 

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  • #3
eventob said:

Homework Statement


Two objects A and B, with masses m1=1.00kg and m2=2.00kg, are connected with an ideal string. Object A is moving on an ideal incline with 0 friction. Object B is moving vertically. A force F is working on object B. Its magnitude is 6.00N. Object b is accelerating downward, with a magnitude og 5.50 m/s^2.

a) Draw a free body diagram for the two objects
b) Find the tension force between the objects
c) Find the angle beta


Homework Equations


Newtons second law


The Attempt at a Solution


Made a free body diagram for each object. Then applied Newtons second law in the x-direction of object A and in the y-direction og object B.
A:
sigma F_x=F-T-m1*(sin(beta)=m1*a
Does F show up in this free body diagram? And since the block is accelerating down the plane, you have your signage wrong. And you forgot to include the 'g' for the weight component down the plane.
sigma F_y=n-m1*g*cos(beta)
= ? (no acceleration perpendicular to the plane, but this equation is not needed in this problem)
B:
sigma F_y=f+T-m2*g=ma
signage error...net force is down...choose down direction as positive.
I am not sure whether the force F should be in the free body diagram og object A at all.

Thanks in advance.
That is right, get it out of there...
 

Related to Tension/pulley problem, Newtons second law

1. What is a tension/pulley problem?

A tension/pulley problem is a type of physics problem that involves analyzing the forces acting on an object that is connected to one or more pulleys. The goal is to determine the tension in the ropes or cables that are supporting the object, as well as the acceleration of the object.

2. What is Newton's second law?

Newton's second law, also known as the law of acceleration, states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. This can be expressed as the equation F = ma, where F is the net force, m is the mass of the object, and a is the acceleration.

3. How do you solve a tension/pulley problem using Newton's second law?

To solve a tension/pulley problem using Newton's second law, you first need to draw a free body diagram of the object and all the forces acting on it. Then, use Newton's second law to set up and solve equations for the net force and acceleration of the object. Finally, use these values to calculate the tension in the ropes or cables.

4. What are some common misconceptions about tension/pulley problems?

One common misconception is that the tension in the ropes or cables is always equal to the weight of the object. In reality, the tension can vary depending on the number and arrangement of pulleys. Another misconception is that the acceleration of the object is always equal to the net force divided by its mass. This is only true if there are no other forces acting on the object.

5. What are some tips for solving tension/pulley problems?

Some tips for solving tension/pulley problems include drawing accurate and clear free body diagrams, carefully labeling all forces and variables, and keeping track of units throughout the problem. It can also be helpful to break down the problem into smaller, manageable steps and to double check your calculations for accuracy.

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