Need help with projectile/friction problem.

  • Thread starter Thread starter Shipman515
  • Start date Start date
AI Thread Summary
The discussion revolves around calculating the initial speed of a 100 g object pushed off a table, given its fall distance and landing distance from the edge. The object slides 3.00 m before falling 1.30 m and landing 25.0 cm away, with a coefficient of kinetic friction of 0.500. Participants suggest using energy conservation principles and kinematic equations to find the object's speed as it leaves the table. They emphasize the importance of considering the effects of friction on the object's kinetic energy. The original poster expresses gratitude for the guidance received in solving the problem.
Shipman515
Messages
7
Reaction score
0
A popular pastime is to see who can push an object closest to the edge of a table without its going off. You push the 100 g object and release it 3.00 m from the table edge. Unfortunately, you push a little too hard. The object slides across, sails off the edge, falls 1.30 m to the floor, and lands 25.0 cm from the edge of the table.

If the coefficient of kinetic friction is 0.500, what was the object's speed as you released it?

I've tried a lot of different things, suggestions?
 
Physics news on Phys.org
I don't know if this will help but have u tried

kinetic energy = gravitational potential energy

1mv^2/2 = mgh
 
t = time to fall
y = vertical distance
g = acceleration (9.8m/s^2)
x = distance traveled off table
v1 = initial speed
v2 = speed as object leaves table (x component)


y = (1/2)*g*t^2 therefore t = (2*y/g)^(1/2)
x = v2*t therefore x = v2*(2*y/g)^(1/2)

Maybe someone can finish this for you. I apologize my laptop is dying:(
 
try to figure out the velocity when it leaves the table and starts falling. If you find it, you can find its kinetic energy at the instant. Since there is friction on the table, the kinetic friction caused the mass to be slowed down from the initial velocity it took off from. how much did it slow down, or how much energy did it lose to friction? If you know that than, you can trace back and find the initial velocity.
 
Last edited:
Please keep in mind that the rules of this forum are that the "helpers" should only guide the OP, not do or work out the solution.

Zz.
 
Got it. Thanks ya'll. really helped.
 
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 '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