Tension/pulley problem, Newtons second law

Click For Summary
SUMMARY

The discussion focuses on a tension and pulley problem involving two objects, A and B, with masses of 1.00 kg and 2.00 kg, respectively. Object A is on a frictionless incline, while object B is subjected to a downward force of 6.00 N and accelerates downward at 5.50 m/s². The user initially calculated the tension force as 20.6 N but encountered inconsistencies when attempting to find the angle beta, specifically with the cosine value exceeding 1. The community advised correcting the free body diagram and addressing the sign conventions in the equations derived from Newton's second law.

PREREQUISITES
  • Understanding of Newton's Second Law
  • Ability to draw and interpret free body diagrams
  • Knowledge of trigonometric functions in physics
  • Familiarity with concepts of tension in strings and pulleys
NEXT STEPS
  • Review the application of Newton's Second Law in multi-body systems
  • Study the principles of free body diagrams for inclined planes
  • Learn about the effects of frictionless surfaces on tension calculations
  • Explore the relationship between acceleration and tension in pulley systems
USEFUL FOR

Students studying physics, particularly those focused on mechanics, as well as educators seeking to clarify concepts related to tension, pulleys, and Newton's laws.

eventob
Messages
32
Reaction score
0

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.
 
Physics news on Phys.org
Forgot to upload this earlier. :)
 

Attachments

  • bilde.png
    bilde.png
    2.2 KB · Views: 594
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...
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
Replies
4
Views
1K
  • · Replies 13 ·
Replies
13
Views
2K
Replies
44
Views
4K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
14
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
13
Views
3K
  • · Replies 42 ·
2
Replies
42
Views
6K
  • · Replies 1 ·
Replies
1
Views
2K