Displacement and Height Calculations with Velocity

AI Thread Summary
To determine how long the bullet was in the air, the time can be calculated using the horizontal distance and muzzle velocity, resulting in approximately 0.485 seconds. The height from which the gun was fired can be calculated using the formula for free fall, yielding a height of about 1.15 meters. For the arrow shot at 32.6 m/s, the required height to hit the same target can be calculated, resulting in approximately 0.5 meters. The discussion emphasizes the importance of understanding projectile motion and the effects of gravity on objects in free fall. Accurate calculations are essential for solving these physics problems effectively.
sugar1
Messages
3
Reaction score
0
1. Homework Statement [/b]

assume g = 9.81 m/s2, and friction can be ignored.

A gun is fired horizontally at a target lying on the ground 188 m away, and the bullet hits the center of the target. The muzzle velocity of the gun (the speed with which it fires bullets) is 387 m/s.

a) How long was the bullet in the air?
in seconds

b) How high was the gun above the ground when it was fired?
in meters

c) Suppose an arrow can be shot out of a bow at 32.6 m/s. How high above the ground would you have to fire the arrow horizontally to hit the same target over the same distance?
in meters

NOTE: Think about how high this is in feet.
 
Physics news on Phys.org
So what did you come up with for a)?
 
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