Highschool Physics Question Homework Help

[GoonMcFly]

Homework Statement

Hey everyone, I'm new to this forum so Let me first introduce myself to the community. I am a grade 11 High school student from Toronto, Canada. I have joined this forum in hopes of gaining access to support whenever i need help on my Physics homework. I have a question..

So there is a Cart that weights 0.521 Kg and its on a frictionless track and its attached to a string that attaches it to a weight of an UNKNOWN MASS through a frictionless pulley.
The Track is 1 Meter long, How much mass (UNKNOWN MASS) would be required to pull the cart down to the end of the track (total distance: 1 meter) in 2 seconds? The cart travels at a constant velocity so there is no acceleration.

This picture simplifies the question.
http://i.imgur.com/083cve3.jpg?1

Homework Equations

The Big 5 Equations.

The Attempt at a Solution

I have figured that I am solving for the Applied Force.
I'm new to Physics so I am understandably stuck.

 

[BrettJimison]

Think of it like this:
F=ma.
You have the MASS of that cart. If you can find its acceleration, then you can find the force in Newtons. You can then convert those Newtons into kilograms, thus finding the mass of the weight.

 

[BrettJimison]

You can find acceleration by your distance formula. This problem wouldn't make sense if the cart had a constant velocity. If its velocity was constant, there would be no force acting on it.

 

[CWatters]

Think of it like this:
F=ma.
You have the MASS of that cart. If you can find its acceleration, then you can find the force in Newtons. You can then convert those Newtons into kilograms, thus finding the mass of the weight.

The net force on the cart is not the weight when it's accelerating.

If I remember correctly when you apply F=ma to work out the tension F the mass m is the sum of the weight and cart.

 

[Nickie]

Hi there! Welcome to the forum. It's great to see that you're taking an interest in physics and seeking help when needed.

To solve this problem, we can use Newton's second law, which states that the net force on an object is equal to its mass multiplied by its acceleration. In this case, since the cart is moving at a constant velocity, its acceleration is zero. Therefore, the net force on the cart must also be zero.

We know that the only forces acting on the cart are the weight of the cart itself and the tension in the string. Since the track is frictionless, there is no friction force. This means that the tension in the string must be equal to the weight of the cart.

We can set up an equation to represent this:

Tension = Weight of cart

Since the weight of an object is equal to its mass multiplied by the acceleration due to gravity (9.8 m/s^2 on Earth), we can rewrite this equation as:

Tension = mass of cart x 9.8 m/s^2

Now, we also know that the tension in the string is equal to the force applied by the unknown mass on the cart. So we can set up another equation:

Tension = Force applied by unknown mass

Combining these two equations, we can solve for the unknown mass:

mass of cart x 9.8 m/s^2 = Force applied by unknown mass

mass of cart x 9.8 m/s^2 = Applied force (since we know that the applied force is equal to the tension in the string)

Therefore, the unknown mass is equal to the mass of the cart multiplied by 9.8 m/s^2.

Hope this helps! Let me know if you have any further questions. Keep up the good work with your physics studies!