Calculating Force in a Rifle-Bullet System

In summary, a rifle weighing 50.0 N with a barrel length of 0.750 m shoots a 25.0 g bullet at a muzzle velocity of 320 m/s. Using the equations v2=v02+2ax and F=MA, the magnitude of the force exerted on the rifle by the bullet is 17067 N. It is important to pay attention to units in equations to avoid mistakes.
  • #1
*intheclouds*
19
0

Homework Statement



A rifle weighs 50.0 N, and its barrel is 0.750 m long. It shoots a 25.0 g bullet, which leaves the barrel at a speed (muzzle velocity) of 320 m/s after being uniformly accelerated. What is the magnitude of the force exerted on the rifle by the bullet?

Homework Equations


F=MA
w=mg
v=v0+at
v2=v02+2ax



The Attempt at a Solution


I wasn't totally sure of what I was doing, but this is what I did:
I used the equation: v2=v02+2ax and did-- 3202=0+2(a)(.750) and I got 68266.67 m/s2. I don't know if I did this right, or if I even used the right equation.

Then I used the F=MA equation. F=.25(68266.67) to get 17067 N, but when I typed in that answer to Webassign, it was wrong.



Any help would be greatly apprecitated. Thank you!
 
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  • #2


*intheclouds* said:

Homework Statement



A rifle weighs 50.0 N, and its barrel is 0.750 m long. It shoots a 25.0 g bullet, which leaves the barrel at a speed (muzzle velocity) of 320 m/s after being uniformly accelerated. What is the magnitude of the force exerted on the rifle by the bullet?

Homework Equations


F=MA
w=mg
v=v0+at
v2=v02+2ax



The Attempt at a Solution


I wasn't totally sure of what I was doing, but this is what I did:
I used the equation: v2=v02+2ax and did-- 3202=0+2(a)(.750) and I got 68266.67 m/s2. I don't know if I did this right, or if I even used the right equation.

Then I used the F=MA equation. F=.25(68266.67) to get 17067 N, but when I typed in that answer to Webassign, it was wrong.



Any help would be greatly apprecitated. Thank you!

Check your units on what I bolded in your post. It's good to write out the units of each quantity in your equations, to make sure you don't make mixed-units errors like this. I've found that habit of carrying along units in my calculations to be a huge help.

Welcome to the PF!
 
  • #3


That worked! Thank you so much! You are amazing! =]
I generally get the concepts, but then I make silly little mistakes like that and I can't find where I went wrong.

And thanks for the welcoming!
 

What is a force diagram?

A force diagram is a visual representation of the forces acting on an object. It is commonly used in physics to understand the direction and magnitude of forces, and how they affect the motion of an object.

How do you draw a force diagram?

To draw a force diagram, you first need to identify all the forces acting on the object. Then, draw a dot or arrow to represent each force, labeling each one with its name and direction. Finally, make sure to include a scale to indicate the magnitude of each force.

What types of forces can be represented on a force diagram?

There are four main types of forces that can be represented on a force diagram: gravitational, applied, normal, and frictional. Gravitational forces are those caused by the Earth's gravitational pull, applied forces are those exerted by an external object, normal forces are those exerted by a surface, and frictional forces are those that oppose motion.

What is the importance of using force diagrams in science?

Force diagrams are important in science because they allow us to visualize and understand the forces acting on an object. By accurately representing these forces, we can predict the motion of an object and accurately analyze the effects of different forces on its movement.

Can force diagrams be used in real-life applications?

Yes, force diagrams can be used in many real-life applications, such as engineering, mechanics, and even sports. They help engineers design structures and machines that can withstand different forces, and they can also be used in sports to analyze the forces involved in different movements, such as throwing a ball or jumping.

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