Increasing Force: Velocity, Height Calculation

  • Thread starter Thread starter ShadowDatsas
  • Start date Start date
  • Tags Tags
    Force Increasing
AI Thread Summary
The discussion revolves around calculating the velocity and height of a body subjected to a force described by the equation F=5x + 5, with given parameters including mass, friction coefficient, and angle. The body takes off when the normal force (N) equals zero, leading to the determination of the takeoff position at x=3 meters. The user successfully calculates the initial velocity using energy conservation principles but struggles with the height calculation after the force ceases to act. There is confusion regarding the relationship between the force's work and the height, with a suggestion that the height may relate to the area of the triangle formed by the force, which the user questions. Overall, the thread highlights challenges in applying physics concepts to solve the problem accurately.
ShadowDatsas
Messages
11
Reaction score
0

Homework Statement



(First of all sorry for my English, I don't know any scientific expressions in English...)
A Force given by the type F=5x + 5 (x at metres, F at Newtons) is applied to a body of mass m while it creates (the Force) an angle φ with the horizontal level. The coefficient of friction is μ. (the body will move by doing the numbers) First it asks the velocity of the body, when it takes off the ground. Then, it asks the hight, h of the object, if the force stops after 2 meters (after the takeoff).
Givens: m=1kg, μ=0,2 , φ=30, g=10m/s^2

Homework Equations



F=5x + 5 , T=μ*N (T is friction), N=m*g - F*sinφ
I guess that's it.

The Attempt at a Solution


First of all I don't know how much advanced this problem is therefore I couldn't classify it.
The first question is rather easy.
We know that the body will take off when N=0 (N is the reaction from the ground)
So: F*sinφ + N = mg (the ΣF for the Vertical axis)
By zeroing N we get x=3. The by doing the diagramm of (F*cosφ)(x) and T(x)=mg - F*sinφ
and by calculating the acreage we find both Force's work. By subtracting them we get the Kinetical Energy and thus the velocity.
The second question I think it's impossible, or there is something wrong with the exercise.
I use Principal of Energy Conservation to get: WF - mgh = 1/2mv22 - 1/2mv12.
I know v(1) from the previous question and I can find WF with the same way, with the diagramm. But I can't find the velocity at the final state, or the hight to find the velocity afterwards.
 
Last edited:
Physics news on Phys.org
I've been told that the hight is the same as the area of the triangle that the Force creates, but I think it's wrong...Thanks for your help.
 
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