What is the tesion between the two masses?

  • Thread starter UrbanXrisis
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In summary, the two masses connected by a string are being pulled by a force of F. The total acceleration is a=F/3, which means that the tension could be either 2kg*F/3 or 1kg*F/3. To determine the correct tension, Newton's 2nd law can be applied to either mass. The tension is exerted on both masses, resulting in a tension of F/3 for both the 1kg and 2kg mass.
  • #1
UrbanXrisis
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there are two masses connected by a string:

1kg-----2kg---->F

the 2 masses are being pulled by a force of F

what is the tesion between the two masses?

the total acceleration is a=F/3

this means that the tesion is either 2kg*F/3 or 1kg*F/3

not sure which one?
 
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  • #2
UrbanXrisis said:
the total acceleration is a=F/3
Correct.

this means that the tesion is either 2kg*F/3 or 1kg*F/3

not sure which one?
Figure it out! Pick one of the masses and apply Newton's 2nd law. (You already know the acceleration.)
 
  • #3
right, that's what I'm asking, do I apply it to the 1kg mass or the 2 kg mass?
 
  • #4
You think Newton's 2nd law only works for one of them? :smile:

It better work for either mass. Now, of course, if you pick the correct mass to analyze the problem is easier.

Start by identifying the forces that act on each mass.
 
  • #5
if I apply it to the 1 kg mass... it will be T=F/3

if I apply it to the 2 kg mass... it will be T=2F/3
 
  • #6
Obviously that's not right since there is only one tension in the string.

How many forces act on the 1kg mass? How many forces act on the 2kg mass?
 
  • #7
one force acts on the 1kg mass, 2 forces act on the 2kg mass

does that mean the tension force is only exerted on the 1kg mass?
 
  • #8
You tell me. The string exerts its tension force on anything it's attached to.
 
  • #9
oh, so only the 1 kg mass is effected, so that means the T=F/3
 
  • #10
Both masses are affected, but hte tension in the string generally results from a force applied on BOTH ends. In this problem, both ends have atleast a force of 1kg*F/3 on them, therefore that is the tension.
 
  • #11
Analyzing the 1 kg mass:
[itex]F_{net} = ma[/itex]
[itex]T = (1)(F/3) = F/3[/itex]

Analyzing the 2 kg mass:
[itex]F_{net} = ma[/itex]
[itex]F - T = (2)(F/3) = (2/3)F[/itex] ==> [itex]T = F/3[/itex]
 

1. What is tension?

Tension is a force that occurs when two objects are pulling on each other in opposite directions. It is a type of force that is transmitted through a medium, such as a string or rope.

2. What causes tension between two masses?

The tension between two masses is caused by the force of gravity acting on the masses. Each mass exerts a force on the other, resulting in tension.

3. How is tension calculated?

Tension can be calculated using the formula T = mg, where T is the tension, m is the mass, and g is the acceleration due to gravity. This formula assumes that the masses are connected by a string or rope and are not accelerating.

4. What is the difference between tension and compression?

Tension and compression are two types of forces that occur when an object is subjected to external forces. Tension occurs when two objects are pulling on each other in opposite directions, while compression occurs when two objects are pushing on each other in opposite directions.

5. How does tension affect the motion of objects?

Tension can affect the motion of objects by either accelerating or decelerating them. If the tension is greater than the force of gravity, the object will accelerate in the direction of the tension. If the tension is less than the force of gravity, the object will decelerate in the direction of the tension.

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