Analyzing Force vs. Time graphs

In summary, the conversation revolved around finding the mass of an object given a force versus time graph. It was mentioned that impulse, which is the change in momentum of an object, can be calculated from the area under an F-t graph. However, in order to find the mass, the equation F=ma or F=(mv^2)/r must be used, depending on the scenario. Other factors such as velocity, acceleration, and friction may also need to be considered.
  • #1
physics_wtf
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1. I REALLY need help here! I've been doing pretty good in physics so far this year, but a new quiz devastated me. Here's the problem:
I was given a Force vs. Time graph and a lot of the questions pertained to the mass of the object. How do I find the mass only given a F vs T graph?

Homework Equations


Is there any other data I can obtain from a Force/Time graph? (like acceleration, velocity, or something to do w/ friction)?
 
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  • #2
A force time graph is all about impulse, and impulse is the change in momentum of an object.
 
  • #3
Impulse is given by the area under an F-t graph.

As Kurdt said, impulse is the change in momentum of an object. ie. p2 - p1 or m(v2 - v1) [for constant mass].
 
  • #4
If you're solely given the Force of an object over Time... I don't see how you could find the mass of the object unless you were somehow able to calculate the acceleration.

If the object was traveling around a circular path, and you were given the velocity or able to calculate the velocity and the radius of the circle, then you could substitute (v^2)/r as the acceleration...

But I believe, as in introductory physics, the equation F=ma has to come into play here.
(or F=(mv^2)/r)

NOW, you might have been told that this was a free-falling object, or a nuance similar. In which case, that gives you the acceleration (9.8 m/s^2)- so it may be tricky.
 
  • #5
If it is analysing a collision, which F-t graphs are so often used for, and you know the initial and final velocities, then the mass can be found from the relationship in my last post.
 

FAQ: Analyzing Force vs. Time graphs

1. What is a force vs. time graph?

A force vs. time graph is a graphical representation of the relationship between the force applied to an object and the time during which the force is applied. It is used to analyze the changes in an object's motion and the resulting forces acting on it.

2. How do you interpret a force vs. time graph?

To interpret a force vs. time graph, you need to look at the shape and slope of the graph. A flat line represents a constant force, while a steeper slope indicates a greater force. The area under the graph represents the impulse, which is the change in an object's momentum.

3. What does a horizontal line on a force vs. time graph indicate?

A horizontal line on a force vs. time graph indicates that there is no net force acting on the object. This means that the object is either at rest or moving with a constant velocity.

4. How does the shape of a force vs. time graph relate to an object's motion?

The shape of a force vs. time graph can tell us a lot about an object's motion. A straight line with a positive slope represents a constant force causing the object to accelerate, while a negative slope indicates a deceleration. A curve on the graph represents a changing force or an object with variable acceleration.

5. How can force vs. time graphs be used in real-life scenarios?

Force vs. time graphs are commonly used in real-life scenarios, such as analyzing the motion of a car during a collision or the launch of a rocket. They can also be used to study the forces acting on an athlete during a sports event or to analyze the impact of a force on a structure during an earthquake.

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