Forces using Newtons Second law

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Homework Help Overview

The problem involves a bullet fired into wet clay, where the bullet decelerates uniformly. The scenario provides specific values for the bullet's mass, initial velocity, and the distance it travels before coming to rest, prompting a calculation of the average force exerted on the block of clay.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss using kinematic equations to determine the bullet's acceleration and subsequently apply Newton's second law to find the net force. There are inquiries about how to find acceleration and whether it can be negative, as well as discussions about the implications of negative force values.

Discussion Status

The discussion is active, with participants exploring different interpretations of acceleration and force. Some have provided hints about using kinematic equations, while others are questioning the validity of negative values for acceleration and force. There is no explicit consensus on the correct approach or values yet.

Contextual Notes

Participants are working under the constraints of a homework assignment, which may limit the information they can use or the methods they can apply. The original poster has received multiple incorrect answers, indicating a need for further exploration of the problem setup and calculations.

gotpink74
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Homework Statement


A bullet fired into wet clay will decelerate fairly uniformly. If a 10 g bullet hits a block of clay at 235 m/s and comes to rest in 17 cm, what average force does it exert on the block? [Hint: From the fact that the bullet goes from vi to 0 in a distance s, you can find aav and with that Fav.]


Homework Equations


ƩF=mg


The Attempt at a Solution


These are all of the answers I have gotten wrong
46.94 N

13.82 N

23.5 N
 
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The hint is telling you to use one of the kinematic equations to solve for the acceleration of the bullet. Once you solve for it, then use Newton 2 in the horizontal direction to solve for the net force acting on it in the horizontal direction.
 
how do you find the acceleration of the bullet
 
gotpink74 said:
how do you find the acceleration of the bullet

Look up and memorize the kinematic equations for constant accelertion. pick the one that works best for the given problem. The bullet travels a given distance in the block with a given initial speed. It's final speed is 0 after it travels the given distance in the block.
 
is it possible for the acceleration to be negative
 
gotpink74 said:
is it possible for the acceleration to be negative
Why sure. Like when you hit the brakes, the car is moving forward in a positive direction, but the acceleration is in the negative direction, with the braking force acting in the negative direction to slow the car down. If you then hit the gas pedal, the car speeds up again and the acceleration is positive.
 
can the force be negative i got -1624.26
 
gotpink74 said:
can the force be negative i got -1624.26
Yes, you are quite right :approve:, but don't forget the units and round off the answer to say F = -1600 N.
 

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