Glider pulled by suspended mass

  • Thread starter Thread starter slapshot151
  • Start date Start date
  • Tags Tags
    Mass
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
3 replies · 3K views · last reply
slapshot151
Messages
6
Reaction score
0

Homework Statement



A 1.00-kg glider on a horizontal air track is pulled by a string at an angle θ . The taut
string runs over a pulley and is attached to a hanging object of mass 0.500 kg . (a) Show that the speed vx of the glider and the speed vy of the hanging object are related by vx = uvy, where u = z(z2–h02)–1/2. (b) The glider is released from rest. Show that at that instant the acceleration ax of the glider and the acceleration ay of the hanging object are related by ax = uay.


Homework Equations



vy2+h02=z2 (i think...)

The Attempt at a Solution



having problems with part b)
i tried to obtain vx=uvy by deriving the following equation by t:

vy2+h02=z2

see attachment for my attempt.

i've been working on this one problem for a few hours now... i don't get it
 
Attachments
  • Diagram of a glider on an air track pulled by a string over a pulley to a hanging mass m, with labels z, h0, θ, vx on the glider and vy on the hanging mass.
    p4-49.gif
    25.6 KB · Views: 540
  • Handwritten derivation differentiating v_x = (1/2)(z^2 - h_0^2)^(-1/2)(2z dz/dt - 2h_0 v_y) through several steps to v_x = z(z^2 - h_0^2)^(-1/2)(dz/dt - h_0 v_y / z), ending with the note 'I don't understand how to simplify to v_y...'
    a.jpg
    16.8 KB · Views: 419
Physics news on Phys.org
Draw the triangle incorporating z, ho, and x. What is x in terms of the other variables?

When the hanging mass falls a given distance, what happens to the length of z? How does x change when z changes? How does a change in the length of z relate to the velocity of the falling mass?

Hint: Differentiation is required, and then an application of the chain rule.