Thread replies: 14
Thread images: 2
Thread images: 2
File: fuckingshit.png (37KB, 1460x359px) Image search:
[Google]
37KB, 1460x359px
Hey sci, listen I need someone to help me solve this shit, I'm struggling with picrealated concept and this specific exercise is killing me, how do I calculate the resulting Net force?
problem says " the car Z pulls the mass m=900 kg on a 45° plane. acceleration is constant and 1.2 m/s^2 calculate the force in the cord S (answer is 4952 N)
so I know that with taht config the net force of the block is 2S but during the free body diagram I fail to see how shit piles up. I have exam soon, help a broda
>>
or if you could just tell me where is ti appropriate to ask this shit, I can't do it by myself
>>
>>8176893
Worksafe requests would have been appropriate, but whatever.
Three components: friction between the block and the slope, gravity acting on the block, and acceleration of the block. Any questions on how to figure those out? Or is the problem with vector addition?
>>
sorry, but yeah I made those but vector addition doesn't do the job, pic related with my solutions.
>>
it must be something with acceleration, that changes the g force somehow, I can't figure out the FBD
>>
>>8176981
The bend sent me for a loop. The force diagram on the block should have 2 tension forces moving upward while the friction (resisting upward motion) and gravity point downward. There is a net acceleration on the block of a/2 (imagine if the block was at the half way point on the cord and notice it would only move half the distance that you would have to pull the cord to make it taut).
So, sum up the forces:
[math]F_{net} = 2T - F_\mu - F_g [/math]
[math]ma/2 = 2T - \mu m g \cos(\theta) - m g \sin(\theta)[/math]
[math]T = m[a/2 + g (\mu \cos(\theta) + \sin(\theta))][/math]
>>
>>8177039
dropped the division by 2 in last equation
>>
>>8176893
Which F is needed to accelerate m up the slope at a/2? S is then F/2.
Visualize what's going on by setting it in motion:
F = Fg + Ff + Fa
F = m*g*sin(b) + µ*m*g*cos(b) + m*(a/2)
S = F/2
Result given is correct
>>
ahaaa, oh my god it was so simple haha
the T force (or S but we know what we mean) is to be considered part of the equation that gives out m*a, thanks, many thanks indeed
>>
>>8177039
how did you write nice equations like that on 4 chan btw?
>>
>>8177138
It's called mathjax (the syntax is similar to latex). On the top left of your quick reply window there is TEX written. If you click that you can preview what you write
>>
[math]sqrt 2 = x^2/5[/math]
>>
>>8177158
hate latex, have to write reports in it, hate it..
anyway, thanks again for help, much saved I understood better!
[email protected] in case I can return the favor
>>
>>8177177
It's the language of scientific writing. Very useful if you plan on pursuing a field in academia (or publishing in general).
GL on your studies
Thread posts: 14
Thread images: 2
Thread images: 2