• Support PF! Buy your school textbooks, materials and every day products Here!

Newton's Laws of Motion - Force Problem

  • Thread starter Yshai24
  • Start date
  • #1
6
0

Homework Statement


A 0.075-kg arrow hits the target at 21 m/s and penetrates 3.8cm before stopping. (a) What average force did the target exert on the arrow? (b) What average force did the arrow exert on the target? (c) An identical arrow strikes the target at 42m/s. If the target exerts the same average force as before, what's the penetration depth?

Known: mass: .075kg velocity (?) 21m/s, displacement: 3.8cm

Homework Equations


Here I am a little confused. (Or a lot confused)
Fnet=m x a

a=velocity final squared - velocity initial squared / 2(Δ)? Not sure if this equation applies

The Attempt at a Solution


I used the equation to figure out the acceleration since I have the mass. So here is where I am at:
a=0-(21m/s)2 / 2(.038m) = -5.8 x 10^3 m/s2

Then I used that to find Fnet=m x a = (.075kg)(-5.8 x 10^3m/s2)= -435N

I feel like I am on a completely wrong track and am not sure how to answer the question. Is the target applying a force of -435N?

Any help in the right direction is greatly appreciated, thank you for your time.

V/r
Jesse
 

Answers and Replies

  • #2
PhanthomJay
Science Advisor
Homework Helper
Gold Member
7,147
491
Looks good! Yes , if the arrow is moving left to right, the target applies a force on the arrow of 435 N to the left. What force and in what direction does the arrow apply on the target?
 

Related Threads on Newton's Laws of Motion - Force Problem

  • Last Post
Replies
13
Views
858
  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
5
Views
4K
  • Last Post
Replies
3
Views
2K
Replies
6
Views
32K
Replies
5
Views
7K
Replies
1
Views
727
Replies
2
Views
4K
Replies
3
Views
11K
Replies
3
Views
2K
Top