Qualification > Math
All Mechanics DOUBTS HERE!!!
astarmathsandphysics:
see attachment
LekhB:
Thank you!
I had some problems with this one too.
A box of mass 4.5 kg is pulled at a constant speed of 2 m/s alone a rough horizontal floor by a horizontal force of magnitude 15 N.
(i) Find the coefficient of friction between the box and the floor.
The horizontal pulling force is now removed. find
(ii) the deceleration of the bx in the subsequent motion
(iii) the distance travelled by the box rom the instant the horizontal force is removed until the box comes to rest.
And this one too:
A particle of mass 0.5 kg is placed on a rough plane inclined at an angle ? to the horizontal where sin ?= 4/5. Initially, the particle is at rest under the action of a force P N applied in a upward direction parallel to the plan. Given that the coefficient of friction between the particle and the plan is 2/5, calculate the value of P when
(i) the particle is about to move up the plane,
(ii) the particle is about to move down the plan.
If the force P is now removed, calculate the acceleration of the particle down the plane.
sweetsh:
--- Quote from: LekhB on February 26, 2012, 02:56:48 pm ---Thank you!
I had some problems with this one too.
A box of mass 4.5 kg is pulled at a constant speed of 2 m/s alone a rough horizontal floor by a horizontal force of magnitude 15 N.
(i) Find the coefficient of friction between the box and the floor.
The horizontal pulling force is now removed. find
(ii) the deceleration of the bx in the subsequent motion
(iii) the distance travelled by the box rom the instant the horizontal force is removed until the box comes to rest.
And this one too:
A particle of mass 0.5 kg is placed on a rough plane inclined at an angle ? to the horizontal where sin ?= 4/5. Initially, the particle is at rest under the action of a force P N applied in a upward direction parallel to the plan. Given that the coefficient of friction between the particle and the plan is 2/5, calculate the value of P when
(i) the particle is about to move up the plane,
(ii) the particle is about to move down the plan.
If the force P is now removed, calculate the acceleration of the particle down the plane.
--- End quote ---
Hello,
I apologize I won't be able to answer your question i'm on my mobile now but a very good hint is in every question like that, draw the plane inclined with the particular object as a "block" or a "circle" and then put arrows for each force acting on it(i.e gravity, friction, N, .... )
astarmathsandphysics:
Yes draw a diagram. See attachment.
WARRIOR:
A particle P moves along the x-axis . At t seconds (where t =>0 ) the velocity of P is
[3t(sq) -12t + 5 ] m/s
When t=0 , P is at ORIGIN O. Find
a) The velocity of p when its acceleration is zero
b)the values of t when p is again at O
c) The distance travelled by p in the interval 3=<t=<4
i got a and b but i dont get c at all.
I understand by getting the maximu displacement , when V = 0 , i get 13.12... . And at t = 3 displacement is -12 , and at t= 4 displacement is -12 again ! So displacement must be
(13.12-12)X2 ?? explain please the right answer is 48
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