Recent content by dvep

Homework Statement I am doing a past paper question, it is shown in the attached JPEG. I have done part A and got 2.74 rads/s. and in my notes ( as we done the solution in class) it says the elastic potetntial energy is 56.27 J, then it goes on to say that when the bar hits horizontal...

9By +12 - (9*5*6.5) -(7*4) = 0 By= 34.28 I'm am still a bit unclear on the moments when they are positive and negative, is what I said before correct, when they are to the left of the point and clockwise , they are positive?

When the moment is clockwise to the left of the point it is positive? moment about D: 9By +12 - (9*5*2.5) -(7*4) = 0 Is that correct now?

Homework Statement Calculate the reaction forces at B and D See attached jpeg. The Attempt at a Solution sum of vertical forces By + Dy = 7 + (9*5) Do I then solve for the moment about D or A or B? for moment about D i have: -Dy -7 -(9*5)+9By+(12*2)=0 is this correct, please explain to...

Thanks for your reply. I have a fair understanding of it, but still quite confused on how to do this problem and where all the different equations are coming from. Do I find the steady-state solution and use that to find k?

b is the amplitude of the oscillation and \omega is the angular velocity. what do you mean by where is it applied?

Any help at all would would be appreciated with this, really stuck.

Homework Statement The figure attached shows the meter used to study the motion yB = bsinωt. The motion of the mass relative to the frame is recorded on the drum. If l1= 360 mm, l2= 480 mm, l3= 600 mm, m = 0.9 kg, c = 1.4 Ns/m and ω = 10 rad/s, Determine the range of the spring...

Thank you for your help.

0.4 m? so, EPE1 + GPE1 + RotKE1 = EPE2 + GPE2 + RotKE2 40.723 + 0 + 0 = 0 + 25.088 + 15.635

The GPE is 0 at the initial position and 50.157 J when vertical? The center of mass gains translation kinetic energy?

Thank you for your reply it does help. Now with a load impedance I now need to calculate: primary current, secondary current, secondary apparent power, secondary reactive power, the effiency, primary power factor, secondary voltage, secondary real power, secondary power factor, and voltage...

I'm still lost. What do you mean measure the height from the surface? Will the center of mass move towards the end of the bar?

I thought that might be wrong GPE1=mglcos(theta)= 6.4*9.8*0.8*cos(1.571) = 50.157 J GPE2=mglcos(theta)= 6.4*9.8*0.8*cos(0) = 50.157 J Is that correct, they are both the same. So what I get, EPE1 + GPE1 + RotKE1 = EPE2 + GPE2 + RotKE2 40.723 + 50.157 + 0 = 0 + 50.157 + 40.723...

So, EPE=40.723 J GPE=50.176 J Am I meant to add these together to get the total energy, then at the vertical position they both equal 0 and rotational kinetic energy equals the total energy, then use the rotational kinetic energy formula and rearrange to find the angualr velocity w?