# The attachment I posted would have the graphs or p…

### Question Description:

20.50

The attachment I posted would have the graphs or picture need to answer some of the questions I believe. Can you post work and formulas used to answer questions!! Thank you Physics 231 Set 7 Point masses in a plane: CM Three spherical masses are located in a plane at the positions shown below. The masses are Q=0.800 kg, R=0.700 kg, and S=0.400 kg. Calculate the x and y coordinates of the Center-of-Mass of this three mass system. XCM = YCM = Tension in cable A 34.0 kg uniform beam is attached to a wall with a hinge while its far end is supported by a cable such that the beam is horizontal. If the angle between the beam and the cable is θ = 58.0° what is the tension in the cable? Moment of Inertia of 3 masses in a plane Three small spherical masses are located in a plane at the positions shown below. The masses are Q=0.300 kg, R=0.500 kg, and S=0.600 kg. Calculate the moment of inertia (of the 3 masses) with respect to an axis perpendicular to the xy plane and passing through x=0 and y=-1. [Since the masses are of small size, you can neglect the contribution due to moments of inertia about their centers of mass.] Motion on a circle A small mass M attached to a string slides in a circle (x) on a frictionless horizontal table, with the force F providing the necessary tension (see figure). The force is then increased slowly and then maintained constant when M travels around in circle (y). The radius of circle (x) is twice the radius of circle (y). M’s angular velocity at x is one quarter that at y. M’s angular momentum at y is …. that at x. While going from x to y, there is no torque on M As M moves from x to y, the work done by F is …. 0. M’s kinetic energy at x is one quarter that at y. Pivoting cylinder (4 parts) a.) M, a solid cylinder (M=1.55 kg, R=0.137 m) pivots on a thin, fixed, frictionless bearing. A string wrapped around the cylinder pulls downward with a force F which equals the weight of a 0.830 kg mass, i.e., F = 8.142 N. Calculate the angular acceleration of the cylinder. b.)If instead of the force F an actual mass m = 0.830 kg is hung from the string, find the angular acceleration of the cylinder. c.)How far does m travel downward between 0.470 s and 0.670 s after the motion begins? d.)The cylinder is changed to one with the same mass and radius, but a different moment of inertia. Starting from rest, the mass now moves a distance 0.639 m in a time of 0.570 s. Find Icm of the new cylinder. Pivoting rod A uniform rod of length 1.15 m is attached to a frictionless pivot at one end. It is released from rest from an angle θ = 25.0° above the horizontal. Find the magnitude of the initial acceleration of the rod’s center of mass. serway_P08-01 If the torque required to loosen a nut that is holding a flat tire in place on a car has a magnitude of 47 N*m, what minimum force must be exerted by the mechanic at the end of a 24-cm lug wrench to accomplish the task? serway_P08-22 (2 parts) ** A 30-kg floodlight in a park is supported at the end of a horizontal beam of mass 6 kg that is hinged to a pole, as shown in the figure above. A cable at an angle of 30° with the beam helps to support the light. a.)What is the tension in the cable b.)What is the magnitude of the force between the two poles at the point where they intersect? Bicycle A bicycle is moving at a speed v = 2.96 m/s. If the radius of the front wheel is 0.450 m, how long does it take for that wheel to make a complete revolution? serway_P08-07.problem (2 parts) a.)The arm shown above weighs 46.5 N. The force of gravity acting on the arm acts through point A. Determine the magnitudes of the tension force Ft in the deltoid muscle. b.)Find the magnitude of the force Fs exerted by the shoulder on the humerus (upper-arm bone) to hold the arm in the position shown. serway_P08-39.problem (3 parts) A solid 17-kg cylinder rolls without slipping on a rough surface. At an instant when its center of gravity has a speed of 6.6 m/s. Determine: a.)the kinetic energy due to the motion of the center-of-mass. (ignoring rotation) b.)** the kinetic energy due to rotation of the block about its center-or-mass. c.)** the total kinetic energy. serway_P08-40.problem The net work done in accelerating a propeller from rest to an angular speed of 32 revolutions/s is 3100 J. What is the moment of inertia of the propeller? serway_P08-42.problem (2 parts) A car is designed to get its energy from a rotating flywheel with a radius of 1.95 m and a mass of 500 kg. The flywheel can be considered as a uniform thin cylinder. Before a trip, the flywheel is attached to an electric motor, which brings the flywheel’s rotational speed up to 4600 rev/min. a.)What is the kinetic energy stored in the flywheel? b.)If the flywheel is to supply energy to the car as would a 20-hp motor, find the length of time the car could run before the flywheel would have to be brought back up to speed. serway_P08-46.problem Halley’s comet moves about the Sun in an elliptical orbit, with its closest approach to the Sun being 0.59 A.U. and its greatest distance being 35 A.U. (1 A.U. = Earth-Sun distance). If the comet’s speed at closest approach is 54 km/s, what is its speed when it is farthest from the Sun in km/s? You may neglect any change in the comet’s mass. serway_P08-48.problem (2 parts) A playground merry-go-round of radius R = 1.85 m has a moment of inertia I = 250 kg*m2 and is rotating at 12 rev/min about a frictionless vertical axle. Facing the axle, a 24-kg child hops onto the merry-go-round, and manages to sit down on the edge. a.)What is the moment of inertia of the merry-go-round with the child included? b.)What is the new angular speed of the merry-go-round in rev/min? serway_P08-51.problem (5 parts) The puck in the figure has a mass of 0.19 kg. Its original distance from the center of rotation is 40 cm, and the puck is moving with a speed of 90 cm/s in a circle. The string is pulled downward until the center of rotation has moved to r=16 cm. The table is effectively frictionless. a.)What is the original angular momentum of the puck? b.)What is the angular momentum after the puck has moved to r=0.16? c.)What is the original moment of inertia? d.)What is the moment of inertia after the puck has reached r=0.16? e.)How much work was done in pulling the string? skaterconcept.problem A figure skater is spinning with her arms and one leg extended as far as she can. She then pulls them in tight to her body. As her position contracts, her angular momentum ___________. her angular velocity ___________. her rotational kinetic energy __________________. her moment of inertia _______________. Bicycle Problem A bicycle has wheels with a diameter of 0.63 m. It accelerates uniformly and the rate of rotation of its wheels increases from 183.0 rpm to 295.0 rpm in a time of 18.7 s. Find the linear acceleration of the bicycle. Walking on a Circular Platform A large horizontal circular platform (M=79.1 kg, r=3.03 m) rotates about a frictionless vertical axle. A student (m=65.3 kg) walks slowly from the rim of the platform toward the center. The angular velocity ω of the system is 2.30 rad/s when the student is at the rim. Find ω (in rad/s) when the student is 2.61 m from the center. Rolling Masses The five masses below all have the same radius and a cylindrically symmetric mass distribution. They start to roll down an inclined plane, starting from rest, at the same time and from the same height. Give their order of arrival at the bottom (i.e. ABCDE, DCBAE). A) Icm= 1343g cm2, M= 41g B) Icm= 1225g cm2, M= 41g C) Icm= 1278g cm2, M= 50g D) Icm= 1254g cm2, M= 41g E) Icm= 1438g cm2, M= 47g Torque and Students A large plate is balanced at its center and two students of equal mass stand at its center. The plate is rotated on a frictionless pivot about an axis through its center and perpendicular to its face. The students then begin to walk out towards opposite edges. If the students walk at a constant rate, then the plate will have a constant angular acceleration. The rate of rotation … as the students walk outward. The total angular momentum of the system … as the students walk outward. The students produce no net torque on the plate. The students do work in walking outward. Flinstone Bowling The Flintstones and Rubbles decide to try out the new inclined bowling alley, “Bedslant Bowling”. Wilma’s ball and Barney’s ball have the same size, but Barney’s ball is hollow. Fred’s ball and Betty’s ball are scaled down versions of Wilma’s ball and Barney’s ball respectively. They all place their bowling balls on the same pitch incline and release them from rest at the same time. The time it takes for Barney’s ball to hit the pins is …. that for Betty’s ball to hit. The time it takes for Barney’s ball to hit the pins is …. that for Fred’s ball to hit. The time it takes for Wilma’s ball to hit the pins is …. that for Fred’s ball to hit. The time it takes for Barney’s ball to hit the pins is …. that for Wilma’s ball to hit. The time it takes for Betty’s ball to hit the pins is …. that for Fred’s ball to hit. The time it takes for Betty’s ball to hit the pins is …. that for Wilma’s ball to hit.,I don’t know if you received these questions I asked on a previous homework assignment but I am just gonna re-post it with this new homework set! Thank you for the other answers. I seemed to be having trouble trying to submit a few of these questions!! Air puck on a table 1.)An air puck of mass 0.658 kg is tied to a string and allowed to revolve in a circle of radius 1.01 m on a frictionless horizontal table. The other end of the string passes through a hole in the center of the table, and a mass of 1.17 kg is tied to it as seen in the figure. What is the magnitude of the force which causes the centripetal acceleration of the puck? -needed help Rotating Space Station 2.)A proposed space station includes living quarters in a circular ring 63.0 m in diameter. At what angular speed should the ring rotate so the occupants feel that they have the same weight as they do on Earth? We assume that everyone lives at the given diameter. The rotation is around an axis through the center and perpendicular to the circle. -units need to be in rad/s answer given was not accepted answer given 24.86 m/sec Race track 3.)A section of a high speed test track is circular with a radius of curvature R = 1600 m. At what angle of θ should the track be inclined so that a car traveling at 61.0 m/s (136 mph) would keep moving in a circle if there is oil on that section of the track, i.e., it would not slip sideways even with zero friction on that section. (Hint: The car’s vertical acceleration is zero.) Highway exit -answer giver was wrong Θ = 13.71o Escape velocity 6.) The escape velocity of a bullet from the surface of planet Y is 1951.0 m/s. Calculate the escape velocity from the surface of the planet X if the mass of planet X is 1.29 times that of Y, and its radius is 0.903 times the radius of Y. Write an expression for the escape velocity in each case, using the data given. -answer was wrong V = 1632.32 m/sec serway_P07-02.problem (3 parts) 11.) A wheel has a radius of 3.9 m. How far (path length) does a point on the circumference travel if the wheel is rotated through angles of : answers were wrong for some reason? a.)31°? 1.055 m b.)31 radians? 0.394 m c.)31 revolutions? 379.8 m serway_P07-39.problem (3 parts) 14.) A satellite of mass 190 kg is launched from a site on the Equator into a circular orbit at 3000 km above Earth’s surface. DATA: Rearth=6.38×106 m. Remember that the force of gravity (and therefore the acceleration) scale as 1/r2. a.)What is the acceleration of gravity at this altitude? answer given was wrong 8.948 m/sec2 Tire on a balancing machine 15.) A tire placed on a balancing machine in a service station starts from rest and turns through 12.9 revolutions in 6.48 s before reaching its final angular speed. Calculate its angular acceleration. answer wrong 1.93 rad/sec2 serway_P08-04.problem (3 parts) 16. As part of a physical therapy program following a knee operation, a 11.5-kg object is attached to an ankle and leg lifts are done as sketched in the figure above. a.)What is the torque exerted by the knee when the weight is a the 30-degree angle shown above? Unable to interpret units. answer given 22.563 Nm b.)What is the torque exerted by the knee when the weight is a the 60-degree angle shown above? Unable to interpret units. answer given 39 Nm c.)What is the torque exerted by the knee when the weight is a the 90-degree angle shown above? Unable to interpret units. answer given 45.126 Nm

20.50