Solving Force vs Time Graphs: Velocity Example #37

In summary, the conversation is about a student seeking help with solving a problem involving velocity on a force versus time graph. They are confused and frustrated with the problem and are unsure of how to solve it. Another student suggests using the equation vf = vi + at to find the answer.
  • #1
kk727
54
0

Homework Statement


I was given this worksheet today:
http://www.mrwaynesclass.com/impulse/WS/momentum.pdf

However, I was not in school today nor when we started momentum. So I'm a little confused with the graphs. On a force versus time graph, how do you go about solving for velocity? An example problem would be #37. They give you the answer to be -1 m/s (answers are at the bottom) but how do you get there?


Homework Equations


P=mv
ΔP/ΔT = F
F=ma


The Attempt at a Solution



I figured that impulse (ΔP) would be area under the curve, so I calculated that. But using the force and time on the graph, the impulse didn't match up and I just got all confused and frustrated. Can anyone help?
 
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  • #2
I just realized that the worksheet has two problems that are #37... -_- So I'm doubting that -1 m/s is the answer to this one. I'm still confused with trying to solve it, though!
 
  • #3
kk727 said:
I just realized that the worksheet has two problems that are #37... -_- So I'm doubting that -1 m/s is the answer to this one. I'm still confused with trying to solve it, though!

There is no way it's -1...
Try doing this:
Using F=ma, you can get the acceleration, right? With the acceleration you can use the kinematics equations to get the answer.

You have:
Vi = 0
Acceleration = You find it
Time = 20 s
Vf = ? (solve)

So you can use:
vf = vi + at
 

FAQ: Solving Force vs Time Graphs: Velocity Example #37

What is a force vs time graph?

A force vs time graph is a visual representation of the relationship between the force applied to an object and the time it takes for that force to act. It is commonly used to study the motion of objects and is often used in physics and engineering.

How do you interpret a force vs time graph?

The slope of a force vs time graph represents the acceleration of the object, while the area under the curve represents the change in momentum. The shape of the graph can also indicate the type of motion, such as constant acceleration or deceleration.

How can you use a force vs time graph to calculate velocity?

To calculate velocity from a force vs time graph, you can use the formula v = at + v0, where v is the final velocity, a is the acceleration, t is the time, and v0 is the initial velocity. By finding the slope of the graph and plugging in the values, you can solve for the velocity at a specific time.

What is an example of solving a force vs time graph for velocity?

For example, if a car is accelerating at a constant rate of 5 m/s2, its force vs time graph would be a straight line with a slope of 5. If you wanted to find the velocity after 10 seconds, you would plug in the values for t (10 seconds) and a (5 m/s2) into the formula v = at + v0. Let's say the car's initial velocity was 0 m/s, the calculation would be v = (5 m/s2)(10 s) + 0 m/s, giving a final velocity of 50 m/s.

What are some real-life applications of force vs time graphs?

Force vs time graphs are used in many real-life scenarios, such as analyzing the motion of vehicles, studying the force exerted on the human body during physical activities, and designing roller coasters. They are also used in crash tests to analyze the forces acting on a vehicle during a collision.

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