Projectile Motion — How far from the gun does the bullet land?

  • Thread starter Tinkylo
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  • #1
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Homework Statement:
The bullet fired from a gun on the ground has a velocity v. The x-component of the velocity is 8.4 ms-1 and the y-component of the velocity is 9.2 ms-1. x is the horizontal axis and y is the vertical axis. What is the distance in m between the gun and the point where the bullet hits the ground? Acceleration due to gravity is 9.8ms-2. Assuming there is no air resistance during the bullet's flight.
Relevant Equations:
Not sure
I don't know how to link the x-component and y-component together.
 

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  • #2
haruspex
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I don't know how to link the x-component and y-component together.
Distance, start velocity, final velocity, time, acceleration. For which does the same value apply to both coordinates?
 
  • #3
ehild
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I don't know how to link the x-component and y-component together.
As there is no air resistance, the vertical and horizontal components of velocity are not linked in the problem.Consider the problem as independent horizontal and vertical motions.
 
  • #4
Lnewqban
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Relevant Equations:: Not sure

I don't know how to link the x-component and y-component together.
Don't link those, they are giving you the vertical and horizontal components of the initial velocity in order to facilitate the problem.
Hits:
Purely vertical movement: decelerated while moving up / stop / accelerated while falling down.
Purely horizontal movement: non-accelerated and lasting as much as the up-down vertical movement.
 
  • #5
haruspex
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Don't link those
It's not clear what @Tinkylo means by linking them. My interpretation is finding something that links the horizontal and vertical equations. See my hint in post #2.
 
  • #6
Andrew Mason
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Homework Statement:: The bullet fired from a gun on the ground has a velocity v. The x-component of the velocity is 8.4 ms-1 and the y-component of the velocity is 9.2 ms-1. x is the horizontal axis and y is the vertical axis. What is the distance in m between the gun and the point where the bullet hits the ground? Acceleration due to gravity is 9.8ms-2. Assuming there is no air resistance during the bullet's flight.
Relevant Equations:: Not sure

I don't know how to link the x-component and y-component together.
You can work it out from first principles from the equations for x and y as a function of t (time). This involves finding the value of t when y = 0 and then using that value of t in the equation for x. Or you can use the relationship between range, velocity and launch angle that you may have been given: ##R = \frac{v_0^2 \sin{2\theta}}{g}##. If you use this relationship, you will have to find ##v_0## and the launch angle. Which method do you wish to use?

AM
 

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