Force problem PLEASE guide me in the right direction

In summary, the problem involves two carts of equal mass connected by a rope and a force of 20 N being applied to one of the carts. There is no friction involved and the goal is to determine the tension in the rope. By treating the two carts as one object and using Newton's second law, the acceleration can be calculated. The tension in the rope is then equal to the force needed to give the second cart the same acceleration. The mass of the carts is not needed in the calculation.
  • #1
Byrne
20
0
Cart A is locate din front of cart B and is being pulled by a force of 20 N
. The two carts have the same mass and are connected by a rope. There isn't any friction involved in this problem. Determine the tension in the rope.

What exactly do I need to find here?

I mean, if I assume a mass of 5 kg for each cart, then the force of gravity and normal force for each would be 49 N... the entire system would have a mass of 10 kg then. I just don't know where to go from here. Help!​
 
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  • #2
Well let's work through this...
What causes the tension? Cart A pulling on Cart B (think about you pulling on a string attatched to a cart. Your pulling causes the tension)

So what is the force of Cart A pulling on Cart B? There are 4 forces that you are given to work with. 1) Friction, which is zero 2) Normal Force 3) Gravity 4) The force on Cart B

We know that gravity and the normal cancel, so their insignificant. What about the force on Cart B? How does it relate to Cart A? (I suggest remebering what Newton's third law is...the one about actions and reactions)

Hope that helps
 
  • #3
Since you are not told the mass, call it m (and hope it cancels out in the end!- If it does then using "5 kg" or whatever you like doesn't hurt- but you should first show that it cancels).

(And, by the way, this is horizontal motion with no friction- the force of gravity has nothing whatsoever to do with this problem!)

First think of the two carts as a single object of mass 2m. You know the force so you can calculate the acceleration. Since the two carts are attached by a rope that must have the same acceleration and what you just calculated is it.

But the second cart, alone, has mass m. What force pulling on it alone would give it that acceleration? THAT is the tension in the rope. (Did the m's cancel?)
 
  • #4
You can think like this...

I am assuming that u r applying the force on Cart B (doesnt matter much :D)

You are pulling cart B, and the tension in the string is opposing ur force...however, tension being an internal force of the string, simultaneously helps Cart A to accelerate.

Now if we assume the string to b inextensible, then both the carts have same acc.

So ((F(applied)-Tension)/(Mass of Cart B)) = (Tension/Mass of Cart A)

Solve this to get the tension
 

Related to Force problem PLEASE guide me in the right direction

1. What is a force problem?

A force problem is a type of physics problem that involves calculating the force acting on an object, given certain parameters such as mass, acceleration, and distance.

2. How do I approach a force problem?

The first step in approaching a force problem is to carefully read and understand the given information and identify the known and unknown variables. Then, use the appropriate formula to solve for the unknown variable.

3. What are some common formulas used in force problems?

Some common formulas used in force problems are Newton's second law (F=ma), gravitational force (F=G(m1m2/r^2)), and friction force (F=μN), where F is force, m is mass, a is acceleration, G is the gravitational constant, m1 and m2 are the masses of two objects, r is the distance between them, μ is the coefficient of friction, and N is the normal force.

4. Can you provide an example of a force problem and its solution?

Sure! Let's say we have a 10 kg block being pushed with a force of 20 N. What is the acceleration of the block? Using Newton's second law (F=ma), we can rearrange the formula to solve for acceleration: a=F/m. Plugging in the values, we get a=20 N/10 kg, which simplifies to a=2 m/s^2.

5. What are some tips for solving force problems?

Some tips for solving force problems include drawing a free body diagram, using the correct units, double-checking your calculations, and understanding the relationship between force, mass, and acceleration. It's also helpful to practice solving different types of force problems to improve your skills and understanding.

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