A board of mass 3.0Kg serves as a seesaw for two children. Child A has a mass of 40Kg and sits 2.5m from the pivot point. At what distance x should a child B of mass 25Kg sit from the pivot point so as to balance the seesaw? What is the normal force at the pivot point? Assume the board is uniform and centered over the pivot

A board of mass 3.0Kg serves as a seesaw for two children. Child A has a mass of 40Kg and sits 2.5m from the pivot point. At what distance x should a child B of mass 25Kg sit from the pivot point so as to balance the seesaw? What is the normal force at the pivot point? Assume the board is uniform and centered over the pivot

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 36P: A crane of mass m1 = 3 000 kg supports a load of mass m2 = 10 000 kg as shown in Figure P10.36. The...

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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 crane of mass m1 = 3 000 kg supports a load of mass m2 = 10 000 kg as shown in Figure P10.36. The crane is pivoted with a frictionless pin at A and rests against a smooth support at B. Find the reaction forces at (a) point A and (b) point B. Figure P10.36
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 force of F=(2.00i+3.00j) N is applied to an object that is pivoted about a fixed axle aligned along the z coordinate axis. The force is applied at the point r=(4.00i+5.00j)m. Find (a) the magnitude of the net torque about the z axis and (b) the direction of the torque vector .
The fishing pole in Figure P10.22 makes an angle of 20.0 with the horizontal. What is the torque exerted by the fish about an axis perpendicular to the page and passing through the anglers hand if the fish pulls on the fishing line with a force F=100N at an angle 37.0 below the horizontal? The force is applied at a point 2.00 m from the anglers hands. Figure P10.22
A stepladder of negligible weight is constructed as shown in Figure P10.73, with AC = BC = = 4.00 m. A painter of mass m = 70.0 kg stands on the ladder d = 3.00 m 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.
A boy and a girl are balanced on a massless seesaw. The boy has a mass of 60 kg and the girl's mass is 50 kg. If the boy sits 1.5 m from the pivot point on one side of the seesaw, where must the girl sit on the other side for equilibrium? 8 m B) 1.3 m C) 2.5 m D) 3.0 m
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 η1 on the beam, and the second pivot located a distance ℓ = 4.00 m from the left end exerts a normal force η2. A woman of mass m = 55.0 kg steps onto the left end of the beam and begins walking to the right as shown. The goal is to find the woman’s 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 forcesacting 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 η1 is the greatest? (d) What is η1 when the beam is about to tip? (e) Use as shown to find the value of η2 when the beam is about to tip.(f) Using the result of part (d) and as shown, with torques computed around the second pivot, find the woman’s position x…
Consider a see-saw of total length 5.40m balanced at its center of mass, with a child of mass 35.00kg sitting on the left-most edge. If a second child of mass 46.00kg wants to balance the see-saw, what distance from the pivot point must the second child sit? ____m
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A beam resting on two pivots has a length of L = 6.00 m and mass M = 92.0 kg.The pivot under the left end exerts a normal force n1on the beam, and the second pivot placed a distance ℓ = 4.00 m from the left end exerts a normal force n2. A woman of mass m = 62.5 kg steps onto the left end of the beam and begins walking to the right as in the figure below. The goal is to find the woman's position when the beam begins to tip. (a) Where is the woman when the normal force n1 is the greatest? x = ____m(b) What is n1 when the beam is about to tip?____ N (c) Use the force equation of equilibrium to find the value of n2 when the beam is about to tip.____ N
A beam resting on two pivots has a length of L = 6.00 m and mass M = 94.0 kg. The pivot under the left end exerts a normal force n1 on the beam, and the second pivot placed a distance ℓ = 4.00 m from the left end exerts a normal force n2. A woman of mass m = 51.5 kg steps onto the left end of the beam and begins walking to the right as in the figure below. The goal is to find the woman's position when the beam begins to tip. (e) Using the result of part c and the torque equilibrium equation, with torques computed around the second pivot point, find the woman's position when the beam is about to tip. (part c answer: n1= 0 when the beam is about to tip_x = _____m(f) Check the answer to part (e) by computing torques around the first pivot point.x = ____mExcept for possible slight differences due to rounding, is the answer the same? Yes or No