A student hits a board with an initial speed of 10.0 m/s. The student's hand and the board are in contact for 0.002 second and the speed of the hand decreases to 1.0 m/s during the contact between the board and the hand (the hand is aļways moving forward). The mass of the student's hand and arm is 1.0 kg, and the board has a cross-sectional area A = 10.0 cm². £stimate the shear stress on the board.

A student hits a board with an initial speed of 10.0 m/s. The student's hand and the board are in contact for 0.002 second and the speed of the hand decreases to 1.0 m/s during the contact between the board and the hand (the hand is aļways moving forward). The mass of the student's hand and arm is 1.0 kg, and the board has a cross-sectional area A = 10.0 cm². £stimate the shear stress on the board.

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter10: Rotational Motion

Section: Chapter Questions

Problem 74P: A stepladder of negligible weight is constructed as shown in Figure P10.73, with AC = BC = ℓ. A...

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In Figure P10.40, the hanging object has a mass of m1 = 0.420 kg; the sliding block has a mass of m2 = 0.850 kg; and the pulley is a hollow cylinder with a mass of M = 0.350 kg, an inner radius of R1 = 0.020 0 m, and an outer radius of R2 = 0.030 0 m. Assume the mass of the spokes is negligible. The coefficient of kinetic friction between the block and the horizontal surface is k = 0.250. The pulley turns without friction on its axle. The light cord does not stretch and does not slip on the pulley. The block has a velocity of vi = 0.820 m/s toward the pulley when it passes a reference point on the table. (a) Use energy methods to predict its speed after it has moved to a second point, 0.700 m away. (b) Find the angular speed of the pulley at the same moment. Figure P10.40
A uniform beam resting on two pivots has a length L = 6.00 m and mass M = 90.0 kg. The pivot under the left end exerts a normal force n1 on the beam, and the second pivot located a distance = 4.00 m from the left end exerts a normal force n2. A woman of mass m = 55.0 kg steps onto the left end of the beam and begins walking to the right as in Figure P10.28. The goal is to find the womans position when the beam begins to tip. (a) What is the appropriate analysis model for the beam before it begins to tip? (b) Sketch a force diagram for the beam, labeling the gravitational and normal forces acting on the beam and placing the woman a distance x to the right of the first pivot, which is the origin. (c) Where is the woman when the normal force n1 is the greatest? (d) What is n1 when the beam is about to tip? (e) Use Equation 10.27 to find the value of n2 when the beam is about to tip. (f) Using the result of part (d) and Equation 10.28, with torques computed around the second pivot, find the womans position x when the beam is about to tip. (g) Check the answer to part (e) by computing torques around the first pivot point. Figure P10.28
A stepladder of negligible weight is constructed as shown in Figure P10.73, with AC = BC = ℓ. A painter of mass m stands on the ladder a distance d from the bottom. Assuming the floor is frictionless, find (a) the tension in the horizontal bar DE connecting the two halves of the ladder, (b) the normal forces at A and B, and (c) the components of the reaction force at the single hinge C that the left half of the ladder exerts on the right half. Suggestion: Treat the ladder as a single object, but also treat each half of the ladder separately. Figure P10.73 Problems 73 and 74.
A father and his daughter are playing a see-saw made of a plank of length 5.1 m and of weight 118 N in a park. If the daughter weights 274 N and sits at one edge of the plank, where the father with a weight of 523 N should sits from the pivot point to balance the see-saw in m, assuming that the plank has uniform density? Keep three significant figures.
A 900 N man, 165 cm tall lies on a center of gravity reaction board with his feet at the left end. The reaction board is 206 cm long, weighs 249.2 N, has a uniform distribution of mass, and is supported at both ends by knife-edges. At the right end the knife-edge rests on a scale which reads585 N. Assuming the CG of the reaction board is 103 cm from A, what percentage of his height is his center of gravity (measured from his feet?)
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As shown in the figure below, a stick of length L = 0.425 m and mass m = 0.225 kg is in contact with a rough floor at one end and a frictionless bowling ball (diameter d = 16.00 cm) at some other point such that the angle between the stick and the floor is ? = 30°. Determine the following. (a) magnitude of the force exerted on the stick by the bowling ballN(b) horizontal component of the force exerted on the stick by the floorN(c) vertical component of the force exerted on the stick by the floorN
Two children of mass 15 kg and 35 kg sit balanced on a seesaw with the pivot point located at the center of the seesaw. If the children are separated by a distance of 3.0 m, at what distance, in meters, from the pivot point is the smaller child sitting in order to maintain the balance?
A person carries a plank of wood 2.0 m long with one hand pushing down on it at one end with a force F1 and the other hand holding it up at 50 cm from the end of the plank with force F2. f the plank has a mass of 19 kg and its center of gravity is at the middle of the plank, what is the force F2, in newtons? If the plank has a mass of 19 kg and its center of gravity is at the middle of the plank, what is the force F1, in newtons?
As shown in the figure below, a stick of length L = 0.410 m and mass m = 0.180 kg is in contact with a rough floor at one end and a frictionless bowling ball (diameter d = 20.00 cm) at some other point such that the angle between the stick and the floor is ? = 30°.Determine the following. (a) magnitude of the force exerted on the stick by the bowling ball N(b) horizontal component of the force exerted on the stick by the floor N(c) vertical component of the force exerted on the stick by the floor N
Why is the following situation impossible? A uniform beam of mass mb = 3.00 kg and length ℓ = 1.00 m supports blocks with masses m1 = 5.00 kg and m2 = 15.0 kg at two positions as shown. The beam rests on two triangular blocks, with point P a distance d = 0.300 m to the right of the center of gravity of the beam. The position of the object of mass m2 is adjusted along the length of the beam until the normal force on the beam at O is zero.
A uniform plank of length 2.00m and mass 30.0kg is supported by three ropes, as indicated by the blue vectors in figure p8.27. Find the tension in each rope when a 700-N person is d=0.500m from the left end.