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

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
5 replies · 2K views
Tinkylo
Messages
6
Reaction score
1
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.
 

Attachments

  • 螢幕截圖 2020-02-21 下午3.52.14.png
    螢幕截圖 2020-02-21 下午3.52.14.png
    12.4 KB · Views: 267
Physics news on Phys.org
Tinkylo said:
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.
 
Tinkylo said:
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.
 
Tinkylo said:
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