SRL Archive - NOTA

I've noticed that alot of the people on this forum are extremely intelligent and would probably be fairly good at physics. I was away from school for a few days and missed some physics questions and my teacher gave me some questions to do but forgot to give me the answers. So if someone or some people could do these questions (and show work if you want) to see if I got the same answers it would really help me out.

1. A non-uniform beam with a mass of 85kg has a length of 6.2m and is attached to a wall and supported at an angle of 28 degrees from the wall by a horizontal rope which is attached to the wall above the beam . The tension in the rope is found to be 310N. How far from the pivot point is the center of mass of the beam? The diagram looks like this: [ATTACH=CONFIG]23189[/ATTACH]

2. A uniform diving board is 4.5m long, it's mass is 45kg. A person with a mass of 75kg stands at the end. Support A holds the board at the other end support B is 1.0m away from support A. Calculate the magnitude and direction of the forces support A and B exert.

This diagram looks like this: [ATTACH=CONFIG]23190[/ATTACH]

I know this is a little out of the ordinary but hell it's worth a shot. Hopefully someone knows the answer.

@Turpinator @riwu :)

first one seems simple enough. second one… havent read it yet. ill post as i finish.


1) dist = 1.22683 m
(will do work and stuff too)
excuse my crude paint drawings. i would normally do it on paper, but my scanner being stupid.

2)F_a = 3123.75 N downward, F_b = 4299.75 N upward
am i assuming there is no deformation of the diving board?

Statics! some good shit. remember Newtons 2nd law. You should have 3 equations of equality in 2 dimensions (6 when in 3d). Sum of the forces in the X and Y directions and Sum of the Moment about a point u pick. a moment is a force applied at a point from a distance that you picked. if you have multiple forces reacting at a single point it would be wise to chose that point to sum your moments about because the distance is 0 at that point so all the reacting forces will cancel which means less work :D

if you get a negative answer like turp did above for point a, it just means your initial thought of what the reaction force is doing to the beam was wrong. his answers look right

drawing pictures will help you learn a lot about whats going on especially if you guys start talking about shear and bending moment diagrams or having forces applied over a distance rather than at a point.

@Enslaved;

He is good with physics.

Covered these topics in both physics and maths. It's easy once you know what you're doing but I defo don't miss it one bit :yawn:

Q2: Fa=(1.5*45+3.5*75)*9.81
fb=fa+(45+75)*9.81

@MedChilled just in case you can't find your way back to this thread.

From: Rich
Covered these topics in both physics and maths. It's easy once you know what you're doing but I defo don't miss it one bit :yawn:

This, I actually just finished my physics requirements for my major and I must say, so glad to be done with it!

From: Hazzah
This, I actually just finished my physics requirements for my major and I must say, so glad to be done with it!

I'm majoring in it! :D

haha

I find, if you can get a Free Body Diagram going, usually you are well on your way to the answer

From: Sk1nyNerd
I'm majoring in it! :D

haha

LOLOLOL GG you. That shit sucks!