General Thoughts: Engineering Studies (3 Viewers)

[EpaX]

What did everyone get for MC? I got:
1)C
2)C
3)B
4)C
5)A
6)D
7)A
8)B
9)A
10)A
11)C
12)A
13)C
14)D
15)C
16)B
17)D
18)B
19)C
20)B

Q4 is definitely D, Q10 i think should be B, and Q14 should be B.

 

[orcevalm]

What did everyone get for the Power question? the ferry one? I got o.something KW. its probs wrong

 

[Shackleford]

Q20 should be A. Its a tricky question. You need to calculate 'y' which is 96, as the top half of the beam undergoes compressive stress. 'm' can be calculated by drawing up a basic SFD and BMD, which is 12kNm. Plug it into the bending stress formula, and it would be approximately 11.3MPa. The given area is useless information. Q10 answer:B would make some sense, as you'd average out the radii to get 16.5, which is the radius along the neutral axis. IDK about 14, I put down B for that.

 

[aDimitri]

What did everyone get for the Power question? the ferry one? I got o.something KW. its probs wrong

0.71 something

 

[chrisdelinet]

got that to but i think i got tension

for the truss question BC was 15kn in tension and DF was redundant

 

[aDimitri]

What did everyone get for MC? I got:
1)C
2)C
3)B
4)C
5)A
6)D
7)A
8)B
9)A
10)A
11)C
12)A
13)C
14)D
15)C
16)B
17)D
18)B
19)C
20)B

1)C
2)C
3)B
4)D
5)A
6)D
7)A
8)B
9)A
10)B
11)C
12)A
13)C
14)B (should be D, you were correct)
15)C
16)B
17)D
18)A (pretty sure this is wrong)
19)C
20)A

 

[EpaX]

DF was redundant

omg i spent so long in the exam wondering why equilibrium was being violated :'(

 

[aDimitri]

got that to but i think i got tension

for the truss question BC was 15kn in tension and DF was redundant

BC = (22.5*7.5 - 30*3.75)/3.75 (assumed compression)

 

[chrisdelinet]

Q20 should be A. Its a tricky question. You need to calculate 'y' which is 96, as the top half of the beam undergoes compressive stress. 'm' can be calculated by drawing up a basic SFD and BMD, which is 12kNm. Plug it into the bending stress formula, and it would be approximately 11.3MPa. The given area is useless information. Q10 answer:B would make some sense, as you'd average out the radii to get 16.5, which is the radius along the neutral axis. IDK about 14, I put down B for that.

Q20) B <--- darn this i put 154 into equation
Q10) B <--- just guessed really
Q14) D <--- B had a weird thing in the hole, therefore i reasoned it had to be D

 

[EpaX]

14)B (should be D, you were correct)

But wouldn't that edge be visible for the flange, and it also wouldn't be sectioned because it's not on the cutting plane..?

 

[Shackleford]

The power question would be different. You will need to calculate the new force as instead, you are pulling the boat up the plane which would constitute to a mix of frictional and weight pulling down the plane you'd need to overcome. This means you cannot use the answer from part (i) for this question. I think its approximately 4kW. For that friction boat question/power.

 

[aDimitri]

The power question would be different. You will need to calculate the new force as instead, you are pulling the boat up the plane which would constitute to a mix of frictional and weight pulling down the plane you'd need to overcome. This means you cannot use the answer from part (i) for this question. I think its approximately 4kW.

the F in part i is overcoming the weight.

 

[chrisdelinet]

omg i spent so long in the exam wondering why equilibrium was being violated :'(

i did the calculations and ended up with zero, therefore to double check i looked at the joint F (i believe that it was this joint on the top of my head) and it had three members there. I could not close the force polygon if i tried to include all three members, but i could by omitting DF, therefore im quite certain its redundant. (if you wanted my thought process =D)

 

[Shackleford]

No it said to prevent it from slipping. So friction would be helping you to prevent the boat from sliding down the plane.

 

[chrisdelinet]

No it said to prevent it from slipping. So friction would be helping you to prevent the boat from sliding down the plane.

i can't believe i did not see that, i added them instead (weight component and friction) ...

 

[chrisdelinet]

What did everyone do for that centre of mass question? i used moments from the nose of the plane, but don't know if it was correct or not.

 

[aDimitri]

What did everyone do for that centre of mass question? i used moments from the nose of the plane, but don't know if it was correct or not.

moments from center of mass

 

[aDimitri]

No it said to prevent it from slipping. So friction would be helping you to prevent the boat from sliding down the plane.

ahh now i get what you're saying. ffs that's such a stupid mistake

 

[mirachael]

What did everyone get for MC? I got:
1)C
2)C
3)B
4)C
5)A
6)D
7)A
8)B
9)A
10)A
11)C
12)A
13)C
14)D
15)C
16)B
17)D
18)B
19)C
20)B

Whoops typo I got B for 10. And shit didn't see the compression part for 20. Well there goes my state rank.

 

[mirachael]

18)A (pretty sure this is wrong)

0.16 (A) is what you get when you divide Load over effort. However, the machine isn't necessarily 100% efficient so VR!=MA so you have to find VR on its own. This is basically (2*170/700)*(20/50)=0.19 which is B