Find the Trajectory's Launch Angle

AI Thread Summary
To determine the launch angle for a cannon firing at a hilltop target, the initial calculation using the equation 2θ=arcsin([g*R]/V^2) yields an angle of approximately 6.83 degrees, assuming the projectile lands on flat ground. However, since the target is elevated, the standard projectile motion equation needs to be applied to account for the height difference. The equation h = xtanθ - 0.5gx^2/V^2cos^2θ should be used to solve for the correct angle θ, considering the vertical distance to the hilltop. This adjustment is crucial for accurately hitting the target. The discussion emphasizes the need for a more complex approach to include the elevation in the trajectory calculation.
deveny7
Messages
6
Reaction score
0

Homework Statement



A cannon fires at a hilltop target with a muzzle velocity of V = 600 ft/s. The
horizontal and vertical distances to the target are L = 0.5 miles and h = 0.25 miles.
Determine the elevation angle at which the cannon should be fired.

L=2640 ft
h=1320 ft


Homework Equations



2θ=arcsin([g*R]/V^2)

The Attempt at a Solution



2θ=asin([32.2*2640]/360000)

2θ=asin(.2361)

θ=6.8282

This would be the correct angle if the cannon ball were to hit the ground, but the ball is landing on the hilltop. What equation should be used to include the quarter mile in the air?
 

Attachments

  • HW.jpg
    HW.jpg
    18.4 KB · Views: 469
Physics news on Phys.org
Use the general formula for the projectile.
h = xtanθ - 0.5gx2/v2cos2θ and solve for θ.
 
Thank you!
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top