Energy conservation of a sliding box

AI Thread Summary
A 3.4 kg rock slides down a 33-degree incline starting from 25 cm, and the friction coefficient is 0.19. The user calculates the distance of the incline to be 0.459 meters and determines the velocity at the bottom to be approximately 1.861 m/s. They attempt to apply energy conservation principles to find how far the box slides on the horizontal before stopping, but their calculations yield an implausible distance of 31.01425 meters. The discussion highlights the challenges in correctly applying physics equations to account for friction and energy loss. Accurate calculations are essential for determining the actual sliding distance.
utsharpie
Messages
9
Reaction score
0
3.4kg rock starts at 25 cm on a plane with a 33degree angle. upon reaching the bottom the box slides along the horizontal. friction coeff is
.19. how far does the box slide on the horizontal before coming to a rest?

ok i need to use .5MVi2 + MGy1 = .5MVf2 + MGy2 + Ffrd

first i need to find the velocity of the box as it hits the end of the incline. i also need the length of the incline.

i have Y1=.025 meters
Vf=0
Vi=0
M=3.4kg
g=9.8
theta=33
fr=.19

i keep getting 4.3 meters but its wrong
 
Physics news on Phys.org
ok i found the distance from top of incline to bottom of incline to be .459meters using laws of triangles. so if friction is acting the velocity is gsin33-.19gcos33 and that equals 3.7758

v2=2ad
v2=3.466
v=1.8618

ok so we got Vi at the bottom to be 1.861 and the y1 and y2 at the bottom are both zero and the final V is 0. so is it mv2/2=.19d? and that comes out to 31.01425 meters?no way!
 
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