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vx = v0*cos(53 deg); vy0 = v0*sin(53 deg); and we need -15 = vy0*t - (1/2)gt^2, while 40 = vx*t. (Consider the "v"s to be given in m/s.) -15 = v0*sin(53)*t - (4.9)t^2 and 40 = v0*cos(53)*t. Then v0 = 40/[t*cos(53)], so -15 = 40*tan(53) - (4.9)t^2 => (4.9)t^2 = 68.08 => t = 3.727 => v0 = 17.8 m/s. (part B) If v0 = 8.9 m/s, then vy0 = 7.108 m/s and vx = 5.356 m/s. The time to cross to the other building would be 7.468 seconds, but the time to fall to the ground would be found from -100 = (7.108) t - 4.9 t^2 => 49 t^2 - 71.08 t - 1000 = 0 => t = 71.08/98 + + (1/98)*sqrt(71.08^2 + 4000*49) = 5.30 seconds. So the motorbike would land on the ground, about (40 m)(5.3/7.47) = about 28.4 m away from the base of the first building.
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You have the height of the wall, so we now have two vectors, the vertical height of the wall, and the trajectory of the cannon ball. These can then be resolved into a triangle along with the horizontal component of the force. This makes a right angled triangle with the horizontal and vertical components and the trajectory as the hypotenuse. Trigonometry can then be used (sin=o/h cos=a/h tan=o/a) to determine the length of the horizontal vector, which is the distance from the castle Hope that helps :)
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This is going to be a long answer, but I guarantee it's right. The trick is recognizing the nonlinear nature of the problem, and using Laplace Transforms to find the correct solution to the block's position function: (a) When you draw your free body diagram, assuming no damping or friction effects, let x(t) be the block's position function. Then the net force on the block is simply: mx'' = -kx + F or mx'' + kx = F where F is a constant. This is a differential equation with a solution of: x(t) = (F/k) * [1 - cos(t*sqrt(k/m))] Note that the initial position at t=0 is 0m (equilibrium point). We can solve for the time, to, at which x(t) = .9 m, then find the speed by taking the derivative and substituting the time: .9 = (F/k) * [1 - cos(to*sqrt(k/m))] to = sqrt(m/k) * arccos(1 - .9*(k/F)) to = sqrt(3/19.6) * arccos(1 - .9*(19.6/(20))) to = .56827 seconds Next, the derivative of x(t) is simply: x'(t) = (F/k) * sqrt(k/m) * sin(t*sqrt(k/m)) Substituting the value for to: x'(to) = (20/19.6) * sqrt(19.6/3) * sin(.30788*sqrt(19.6/3)) x'(to) = 2.589 m/s (b) When friction is introduced, the block's equation of motion becomes: mx'' + kx = F - umg where u is the frictional coefficient and g is the gravitational acceleration. Thus, the solution to the position function is: x(t) = ((F - umg)*/k) * [1 - cos(t*sqrt(k/m))] Using the same process as that above: x(to) = .9m = ((F - umg)*/k) * [1 - cos(to*sqrt(k/m))] to = sqrt(m/k) * arccos(1 - .9*(k/((F-umg)))) to = .71332 seconds The velocity function is: x'(t) = ((F-umg)*/k) * sqrt(k/m) * sin(t*sqrt(k/m)) x'(to) = 1.782 m/s FINAL ANSWERS: (a) v = 2.589 m/s (b) v = 1.782 m/s
Physics help!!! i really needed this answer?
The John Hancock Center in Chicago is the tallest building in the United States in which there are residential apartments. The Hancock Center is 343m tall. Suppose a resident accidentally causes a chunk of ice to fall from the roof. What would be the velocity of the ice as it hits the ground? Neglect air resistance.
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The bridge has length B. The train is L meters from the end of the bridge when the student begins to run. The train moves at 90 km / h. The student runs at v km / h. Case 1: The student runs 2/5 B at velocity v while the train travels L at velocity 90 km / h. (2 / 5 ) B v = L ( 90 ) Case 2: The student runs 3/5 B at velocity v while the train travels ( L + B ) at 90 km / h. ( 3 / 5 ) B v = ( B + L ) ( 90 ) Two equations but three unknowns. To continue we must know the length of the bridge or how far from the bridge the train is at the start of the problem.
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Thank you so much for your help! I managed to figure it out using both the answers that were submitted: Nilescio: your method worked perfectly except that you need to replace 2.13m with 1.83m as the mat is 0.30m above the ground. So this changes the velocity which changes the acceleration, which changes the force (the answer is actually 6500N to 2 sig. figs). Somu: to get the right answer, I think you have to use the equation: Work (done by mat) = change in kinetic energy of jumper after contact with mat = K3 - K2 = 0 - 1165.71 = -1165.71 J Work = -1165.71 = Fx (where x = 0.18m) F = -1165.71/0.18 = 6500 N (2 sig. figs) Thankfully I got the right answer in the end. Thanks for all your help!
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I'm going to guess that your numbers are in scientific notation, but just missing the "^" to indicate that things are a power of 10. For example, "3.20 multiplied by 102 kg" is probably 3.20*10^2 kg, or 320kg. The crane power is then 4.00*10^2 = 400w. The force to lift the piano is: F = m*g = 320*9.8 = 3136N The energy consumed is: E = m*g*h = 3136*10 = 31,360J The rate of energy input (or Power, P) is 400W, or J/s, and for a constant power input: E = P*t t = E/P = 31,360/400 = 78.4 s
Do doctors really need physics?
We all need physics in life. What physics means the knowledge of physical laws. A child learns that when you drop anything it falls to ground you do not need to know Newtons law. . You need to know that metals can be converted to knifes and plough and made steel without metallurgy and you need to know the laws of nature. Man used wind to cross the seas. He built boats and ships using wood. He did not need to know Archimedies laws. He new that hot pot will cool. He never knew thermodynamics.A doctor needs to know some basics of natural law.The question is does he need to know the sets formal of laws. He needs to know to the extent that it clashes with his field of medicine. Now he uses modern Machines like X-Ray, CAT, MRI, PET, ULTRA SOUND SCANS, He uses Lasers modern equipments, surgical equipments, optical Microscopes. He needs to know how to operate them and how to interpret the results. He has to use very modern computers for tele-medicine. He uses high speed computers for diagnostics. Thus a doctor has to know enough of Physical Phenomena to work and operate these machines and interpret results.From this interaction we have created great technologies that has helped better medical facilities and we have now great specialist who are great Bio technologists and Bio Engineers.I cannot understand why a question like this is put in a public domain. It is common sense . We all require enough knowledge to be a productive members of the modern societies.Is not the answer is obvious for an educated person.
Is physics really needed for being a neurosurgeon?
Well, this is a question with two answers. First, the obvious, you’ll need physics to enter most medical schools - so, YES!Second, as a neurosurgeon, one’s understanding of basics physics will enhance your life tremendously. While you don’t “need” it, it will certainly help. I say this because I know many neurosurgeons who refuse to use the physics we all learned along the way. Instead, they guess or insist on trial and error when making manipulations. Many physicians don’t bother with Poiseuille's law but it is incredibly valuable and time-saving to know and use. And opting out of the consideration for the basics laws of thermodynamics is like pretending there is no speedometer or fuel gauge on your automobile. Eventually, it is going to cost you. So, sure, you can go without it but of the sciences, you’ll learn as an undergraduate, physics is likely to be the MOST utilized.
Physics Homework help.please help me.I really need it!?
1]A 3 kg mass moves in a circular path of 8 m radius on a frictionless horizontal table. It is attached to a string that passes through a frictionless hole in the center of the table. A second 93 kg mass is attached to the other end of the string.Determine the period (the time for one rev- olution). I'm having a lot of problem figuring this one out.please lay out the solution plan so that i can understand.Thank YOU