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Calculating Net Force results in a final velocity

  • #1

Homework Statement



As simple as the question may seem, I require some honest help. I'm particularly new to physics.

The question is the following:
A net force of magnitude 4.0N acts on a body of mass 3.0kg for 6.0 s. The body is initially at rest.
Which of the following is the speed of the body after the 6.0s interval?

Homework Equations



a = Fnet / m
Fnet = m • a
1 Newton = 1 kg • m/s^2

The Attempt at a Solution


[/B]
I came across this question while browsing some IB tests online for High Level physics and decided to try to solve some of them. Looking at this one, I researched the equations necessary but can't find out how to calculate a net force using only force exerted, mass, and time. On the other hand, I can solve it with both mass and acceleration.
Any tips or equations I haven't found yet? Thank you.
 

Answers and Replies

  • #2
19,920
4,095
Doesn't the problem statement say that the net force is 4 N?

Chet
 
  • #3
Doesn't the problem statement say that the net force is 4 N?

Chet
Sorry, it's asking for the speed of after 6 seconds.
 
  • #4
berkeman
Mentor
56,841
6,821

Homework Statement



As simple as the question may seem, I require some honest help. I'm particularly new to physics.

The question is the following:
A net force of magnitude 4.0N acts on a body of mass 3.0kg for 6.0 s. The body is initially at rest.
Which of the following is the speed of the body after the 6.0s interval?

Homework Equations



a = Fnet / m
Fnet = m • a
1 Newton = 1 kg • m/s^2

The Attempt at a Solution


[/B]
I came across this question while browsing some IB tests online for High Level physics and decided to try to solve some of them. Looking at this one, I researched the equations necessary but can't find out how to calculate a net force using only force exerted, mass, and time. On the other hand, I can solve it with both mass and acceleration.
Any tips or equations I haven't found yet? Thank you.
Sorry, it's asking for the speed of after 6 seconds.
What is the equation of motion for constant acceleration that relates the velocity to the acceleration and the time? You didn't list it in your Relevant Equations...
 
  • #5
19,920
4,095
So what's the acceleration?
 
  • #6
So what's the acceleration?
Honestly, I don't know. The question only offers me a time, mass, and exerted force.
 
  • #7
You didn't list it in your Relevant Equations...
Most likely because I don't know it.
 
  • #8
berkeman
Mentor
56,841
6,821
Honestly, I don't know. The question only offers me a time, mass, and exerted force.
Most likely because I don't know it.
You are showing *very* little effort here. Write out the kinetic equations of motion for constant acceleration for us. That is the best starting point. And you already wrote the equation relating Force, Mass and Acceleration in your first post. So you do too know how to calculate the acceleration. You get these equations from your textbook (most likely your current chapter), and/or you can look them up at wikipedia or Hyperphysics.
 
  • #9
19,920
4,095
In support of what Berkeman said, what does the equation

a = Fnet / m

mean to you? You wrote it down as one of your relevant equations.

Chet
 

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