PS 113 - Quiz 3
10 flashcards · Physics · by Nicholas Enoul
(a) What is the mechanical advantage of a nail puller—similar to the one shown in the figure below—where you exert a force 30 cm from the pivot and the nail is 1.2 cm on the other side? (b) What minimum force (in N) must you exert to apply a force of 1225 N to the nail? (Enter the magnitude.) #9.8 https://www.youtube.com/watch?v=A8nZgN3P3SY
(a) 25 (b) 49 (an attempt at an explanation) The only formula(s) you will be needing to use for both these problems is the following: ---- For (a) ---- \\ With the formula above, we can input the numbers we have directly as: Formula: ME = Li/Lo (because Fo/Fi = Li/Lo) Li = 30cm <--- This is because we are exerting the force from the pivot (aka our input distance) Lo = 1.2cm ME = 30/1.2 <--- Don't need to worry about units bc they cancel out ME = 25 ---- For (b) ---- \\ We use the exact same for…
(a) What is the mechanical advantage of a nail puller—similar to the one shown in the figure below—where you exert a force 50 cm from the pivot and the nail is 1.6 cm on the other side? (b) What minimum force (in N) must you exert to apply a force of 1500 N to the nail? (Enter the magnitude.) #9.8 https://www.youtube.com/watch?v=A8nZgN3P3SY
(a) 31.3 (b) 48 (an attempt at an explanation) The only formula(s) you will be needing to use for both these problems is the following: ---- For (a) ---- \\ With the formula above, we can input the numbers we have directly as: Formula: ME = Li/Lo (because Fo/Fi = Li/Lo) Li = 50cm <--- This is because we are exerting the force from the pivot Lo = 1.6cm ME = 50/1.6 ME = 31.25 ---- For (b) ---- \\ We use the exact same formula, but now we are inputting 1225 as our Fo (applying the force to the nai…
Suppose you needed to raise a 295 kg mower a distance of 6.0 cm above the ground to change a tire. If you had a 1.7 m long lever, where would you place the fulcrum (in m) if your force was limited to 390 N? (Enter the minimum distance measured from your end of the lever.) https://www.youtube.com/watch?v=pn4JLMx0Lss #9.9
Answer: 1.5 (an attempt at an explanation) \\The first step is to figure out what formula to use. For this one, the following should be used: \\From here, there is one last thing we should do. Since the total length of the lever is 1.7m long, that must mean that the sum total of 1.7 meters \\ For reasons that will be apparent soon, we will want to do some basic algebra to substitute Lo with (this is because in the first formula, we want the denominator to be substituted so that we can cross mul…
Suppose you needed to raise a 205 kg mower a distance of 6.0 cm above the ground to change a tire. If you had a 1.2 m long lever, where would you place the fulcrum (in m) if your force was limited to 320 N? (Enter the minimum distance measured from your end of the lever.) https://www.youtube.com/watch?v=pn4JLMx0Lss #9.9
Answer: 1.04 (an attempt at an explanation) \\ The 6.0 cm is a scam, you don't need to ever worry about that! \\The first step is to figure out what formula to use. For this one, the following should be used: \\From here, there is one last thing we should do. Since the total length of the lever is 1.7m long, that must mean that the sum total of 1.7 meters \\ For reasons that will be apparent soon, we will want to do some basic algebra to substitute Lo with (this is because in the first formula,…
What is the final velocity (in m/s) of a hoop that rolls without slipping down a 5.00-m-high hill, starting from rest? https://www.youtube.com/watch?v=r1-gKqMM8AA&t= #10.5
Answer: 7 (an attempt at an explanation) BIG HEADS UP: There are two (or one and a half) ways to solve this problem. Either we can solve it normally, or cheese through it completely. If you want the cheese, simply use the following formula: Final Velocity = sqroot(9.8*height) If you only memorize this "formula", you might not be able to answer the first question on the quiz (what formula to use) since this is the end result of a lot of algebra and physics theory. If you want a 100% chance of so…
What is the final velocity (in m/s) of a hoop that rolls without slipping down a 3.50-m-high hill, starting from rest? https://www.youtube.com/watch?v=r1-gKqMM8AA&t= #10.5
Answer: 5.86 (an attempt at an explanation) BIG HEADS UP: There are two (or one and a half) ways to solve this problem. Either we can solve it normally, or cheese through it completely. If you want the cheese, simply use the following formula: Final Velocity = sqroot(9.8*height) If you only memorize this "formula", you might not be able to answer the first question on the quiz (what formula to use) since this is the end result of a lot of algebra and physics theory. If you want a 100% chance of…
A ball with an initial velocity of 7.33 m/s rolls up a hill without slipping. (a) Treating the ball as a spherical shell, calculate the vertical height (in m) it reaches. (b) Repeat the calculation (in m) for the same ball if it slides up the hill without rolling. https://www.youtube.com/watch?v=0_FbQtzuLSU #10.6
(a) 4.57 (b) 2.74 (an attempt at an explanation) ---- For (a) ---- The very first thing we want to do is use the following formula. I'm not entirely sure how we got there, but it is simple to memorize and relatively similar to chapter 7 (plz watch the video to fully understand): \\ After this, we want to break the KE and PE down into their components (same as from Quiz 2 and Chapter 7). The only difference being KEri having it's own special thing (with "I" and "Omega"). \\ Quick note, after thi…
A ball with an initial velocity of 8.11 m/s rolls up a hill without slipping. (a) Treating the ball as a spherical shell, calculate the vertical height (in m) it reaches. (b) Repeat the calculation (in m) for the same ball if it slides up the hill without rolling. https://www.youtube.com/watch?v=0_FbQtzuLSU #10.6
(a) 5.59 (b) 3.36 (an attempt at an explanation) ---- For (a) ---- The very first thing we want to do is use the following formula. I'm not entirely sure how we got there, but it is simple to memorize and relatively similar to chapter 7 (plz watch the video to fully understand): \\ After this, we want to break the KE and PE down into their components (same as from Quiz 2 and Chapter 7). The only difference being KEri having it's own special thing (with "I" and "Omega"). \\ Quick note, after thi…
(a) What force (in N) must be exerted by the wind to support a 2.40 kg chicken in the position shown in the figure? (Assume r⊥ = 21.0 cm and r'⊥ = 8.20 cm.) (b) What is the ratio of this force to the chicken's weight? (c) Does this support the contention that the chicken has a relatively stable construction? (Yes or No?) https://www.youtube.com/watch?v=gjlPAWNcFwI&t= #9.6
(a) 9.18N (b) 0.39 (c) Yes (an attempt at an explanation) NOTE: I don't know what the hecc I am doing, nor do I entirely know the theory behind this. If you want a good explanation please review the video and visit office hours. ---- For (a) ---- This is all gonna be guesses (not even educated guesses, just shots in the dark), but here goes: \\ We wan't to start with this formula: \\ We now want to break down our ∑τ into it's components. There are two main forces at play: the chickens weight an…
(a) What force (in N) must be exerted by the wind to support a 2.00 kg chicken in the position shown in the figure? (Assume r⊥ = 17.0 cm and r'⊥ = 9.20 cm.) (b) What is the ratio of this force to the chicken's weight? (c) Does this support the contention that the chicken has a relatively stable construction? (Yes or No?) https://www.youtube.com/watch?v=gjlPAWNcFwI&t= #9.6
(a) 10.61 (b) 0.541 (c) Yes (an attempt at an explanation) NOTE: I don't know what the hecc I am doing, nor do I entirely know the theory behind this. If you want a good explanation please review the video and visit office hours. ---- For (a) ---- This is all gonna be guesses (not even educated guesses, just shots in the dark), but here goes: \\ We wan't to start with this formula: \\ We now want to break down our ∑τ into it's components. There are two main forces at play: the chickens weight a…