- #1
Meekin
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I've been asked to research D'Alembert's principle and solve a question. I've looked up quite a lot of different explanations on the internet of D'Alembert's Principle and I'm not quite grasping how to use it. I understand that you rearrange formula so that they equal 0 (e.g. f - ma = 0 or PE - KE = 0 ) so then you can treat them as static problems. I'm just really struggling on how to apply this to a question.
(Gravity to be taken as 9.81ms-2)
KE = (0.5 x (mass x velocity^2))
PE = mass x acceleration due to gravity x height
Final Velocity^2 = Initial Velocity^2 + (2 x Acceleration x Displacement)
I already worked this out using the conservation of energy method and got an answer of Velocity = 8.287ms-1
I then tried playing around with it and realized i could treat it as though it was a box on a horizontal place with no friction
S = 3.5
A = 9.81ms-2
U = 0
V = ?
using v^2 = u^2 + 2as i got the same answer of 8.287ms-1.
This was a guess at a method because its the only other method I've managed to come up with but I'm fairly sure it doesn't use D'Alembert's Principle.
Any help would be appreciated. Thanks guys
Homework Statement
A 25kg box is dropped from a height of 3.5m. Using D'Alembert's Principle work out the velocity reached immediately before hitting the ground.(Gravity to be taken as 9.81ms-2)
Homework Equations
KE = (0.5 x (mass x velocity^2))
PE = mass x acceleration due to gravity x height
Final Velocity^2 = Initial Velocity^2 + (2 x Acceleration x Displacement)
The Attempt at a Solution
I already worked this out using the conservation of energy method and got an answer of Velocity = 8.287ms-1
I then tried playing around with it and realized i could treat it as though it was a box on a horizontal place with no friction
S = 3.5
A = 9.81ms-2
U = 0
V = ?
using v^2 = u^2 + 2as i got the same answer of 8.287ms-1.
This was a guess at a method because its the only other method I've managed to come up with but I'm fairly sure it doesn't use D'Alembert's Principle.
Any help would be appreciated. Thanks guys