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Native people throughout North and South America used a bola to hunt for birds and animals. A bola can consist of three stones, each with mass m, at the ends of three light cords, each with length ℓ. The other ends of the cords are tied together to form a Y. The hunter holds one stone and swings the other two above his head (Figure P11.41a, page 308). Both these stones move together in a horizontal circle of radius 2ℓ with speed v0. At a moment when the horizontal component of their velocity is directed toward the quarry, the hunter releases the stone in his hand. As the bola flies through the air, the cords quickly take a stable arrangement with constant 120-degree angles between them (Fig. P11.41b). In the vertical direction, the bola is in free fall. Gravitational forces exerted by the Earth make the junction of the cords move with the downward acceleration
Figure P11.41
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Chapter 11 Solutions
EBK PHYSICS FOR SCIENTISTS AND ENGINEER
- A child works on a project in art class and uses an outline of her hand on a sheet of construction paper to draw a turkey (Fig. P16.36). The teacher pins the turkey to the bulletin board in the front of the classroom by using a thumbtack. The student notices that if she flicks her finger on the end of the turkey, it oscillates back and forth with a frequency of about 1.65 Hz. If the rotational inertia of the paper turkey is 1.25 105 kgm2 and its mass is 0.005 kg, what is the distance between the thumbtack and the center of mass of the turkey? FIGURE P16.36arrow_forwardAdhesive capsulitis, also known as a frozen shoulder, is a condition that affects the motion of the shoulder joint. The articular shoulder capsule becomes inflamed, stiff, and restricts a person’s mobility. Physical therapy provides one course of treatment for a frozen shoulder. One of the exercises often performed is the pendulum. Here, the patient bends forward and lets the injured arm hang downward and swing freely like a pendulum. The patient slowly swings their arm in a circular motion, for say 10 cycles, and then switches direction and completes 10 more. The patient may hold a light weight dumbbell while performing this motion, or just use an empty hand. Imagine the situation shown in the figure. A patient is moving a 7.0-lb (3.2-kg) dumbbell at constant speed and completes one circular motion of radius 0.40 meters in 1.40 s. What is the angle in degrees?arrow_forwardChapter 10, Problem 069 In the figure, a small disk of radius r=4.00 cm has been glued to the edge of a larger disk of radius R=7.00 cm so that the disks lie in the same plane. The disks can be rotated around a perpendicular axis through point O at the center of the larger disk. The disks both have a uniform density (mass per unit volume) of 1.40 x 103 kg/m3 and a uniform thickness of 6.00 mm. What is the rotational inertia of the two-disk assembly about the rotation axis through O? Number Units the tolerance is +/-2% Click if you would like to Show Work for this question: Open Show Workarrow_forward
- A thin rod of length 0.632 m and mass 66.5 g is suspended freely from one end. It is pulled to one side and then allowed to swing like a pendulum, passing through its lowest position with angular speed 1.35 rad/s. Neglecting friction and air resistance, find (a) the rod's kinetic energy at its lowest position and (b) how far above that position the center of mass rises. (a) Number .0080389 Units J (b) Number .12355 Units 3arrow_forwardA package of mass 5 kg sits at the equator of an airless asteroid of mass 3.0 x 1040 kg and radius 6.3 × 105 m. We want to launch the package in such a way that it will never come back, and when it is very far from the asteroid it will be traveling with speed 237 m/s. We have a large and powerful spring whose stiffness is 1.8 x 105 N/m. How much must we compress the spring? |compression| (a positive number) = %3D Additional Materials leBookarrow_forwardOne end of a cord is fixed and a small 0.400-kg object is attached to the other end, where it swings in a section of a vertical circle of radius 1.50 m, as shown in the figure below. When θ = 23.0°, the speed of the object is 5.50 m/s. An object is swinging to the right and upward from the end of a cord attached to a horizontal surface. The cord makes an angle θ with the vertical. An arrow labeled vector v points in the direction of motion. (a) At this instant, find the magnitude of the tension in the string.Your response is within 10% of the correct value. This may be due to roundoff error, or you could have a mistake in your calculation. Carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. N(b) At this instant, find the tangential and radial components of acceleration. at = Your response differs from the correct answer by more than 100%. m/s2 downward tangent to the circle ac = Your response differs from the correct answer by more…arrow_forward
- One end of a cord is fixed and a small 0.400-kg object is attached to the other end, where it swings in a section of a vertical circle of radius 1.50 m, as shown in the figure below. When θ = 23.0°, the speed of the object is 5.50 m/s. An object is swinging to the right and upward from the end of a cord attached to a horizontal surface. The cord makes an angle θ with the vertical. An arrow labeled vector v points in the direction of motion. (a) At this instant, find the magnitude of the tension in the string.N(b) At this instant, find the tangential and radial components of acceleration. at = m/s2 downward tangent to the circle ac = m/s2 inward (c) At this instant, find the total acceleration.inward and below the cord at °(d) Is your answer changed if the object is swinging down toward its lowest point instead of swinging up? YesNo (e) Explain your answer to part (d).arrow_forwardAn amusement park ride rotates around a fixed axis such that the angular position of a point on the ride follows the equation: θ(t) = a + bt2 – ct3 where a = 1.9 rad, b = 0.75 rad/s2 and c = 0.025 rad/s3.Randomized Variables a = 1.9 radb = 0.75 rad/s2c = 0.025 rad/s3 1) What is the magnitude of the angular displacement of the ride in radians between times t = 0 and t = t1? 2) Determine an equation for the angular acceleration of the ride as a function of time, α(t). Write your answer using the symbols a, b, and c, instead of their numerical values. 3) What is the angular acceleration in rad/s2 when the ride is at rest at t = t1?arrow_forwardA package of mass 8 kg sits at the equator of an airless asteroid of mass 3.0 x 1020 kg and radius 1.3 x 105 m. We want to launch the package in such a way that it will never come back, and when it is very far from the asteroid it will be traveling with speed 208 m/s. We have a large and powerful spring whose stiffness is 2.7 x 105 N/m. How much must we compress the spring? | compression (a positive number) = marrow_forward
- A hollow, thin-walled sphere of mass 11.0 kgand diameter 45.0 cm is rotating about an axle through its center. The angle (in radians) through which it turns as a function of time (in seconds) is given by θ(t)=At2+Bt4, where A has numerical value 1.20 and B has numerical value 1.60. A.What are the units of the constant A? B.What are the units of the constant B? C.At the time 3.00 s , find the angular momentum of the sphere. D.At the time 3.00 s , find the net torque on the spherearrow_forwardPenny is adjusting the position of a stand up piano of mass mp = 150 kg in her living room. The piano is lp = 1.6 m in length. The piano is currently at an angle of θp = 45 degrees to the wall. Penny wants to rotate the piano across the carpeted floor so that it is flat up against the wall. To move the piano, Penny pushes on it at the point furthest from the wall. This piano does not have wheels, so you can assume that the friction between the piano and the rug acts at the center of mass of the piano.Randomized Variables mp = 150 kglp = 1.6 mθp = 45 degrees a) Write an expression for the minimum magnitude of the force Fs in N Penny needs to exert on the piano to get it moving. Assume the corner of the piano on the wall doesn't slide and the static friction between the rug and the piano is μs. Fs,min = b) The coefficient of kinetic friction between the carpet and the piano is μk = 0.27. Once the piano starts moving, calculate the torque τp in N⋅m that Penny needs to apply to keep…arrow_forwardYou have a cylinder. You don't know what its internal structure looks like, but you plan to roll it down a ramp, as in this week's procedure. The ramp is 1 m long, and is elevated at an angle of 15°. The mass of the cylinder is 450 g and its diameter is 2.1 cm.After you release the cylinder, it rolls down the ramp without slipping, gaining speed. How much total energy (in J)does the block have at the bottom of the ramp?arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning