CurrentAtemptmProgiess The figure shows a lower leg being exercised. It has a 49-N weight attached to the foot and is extended at an angle f with respect to the vertical. Consider a rotational axis at the knee, as indicated. (a) When A = 60°, fınd the magnitude of the torque that the weight creates. (b) At what angle () does the magnitude of the torque have a value of 10 N-m? Axis 0.55 m 49 N (a) Number i Units (b) Number Units

CurrentAtemptmProgiess The figure shows a lower leg being exercised. It has a 49-N weight attached to the foot and is extended at an angle f with respect to the vertical. Consider a rotational axis at the knee, as indicated. (a) When A = 60°, fınd the magnitude of the torque that the weight creates. (b) At what angle () does the magnitude of the torque have a value of 10 N-m? Axis 0.55 m 49 N (a) Number i Units (b) Number Units

Physics for Scientists and Engineers: Foundations and Connections

1st Edition

ISBN:9781133939146

Author:Katz, Debora M.

Publisher:Katz, Debora M.

Chapter13: Rotation Ii: A Conservation Approach

Section: Chapter Questions

Problem 14PQ

See similar textbooks

Similar questions

Answer yes or no to the following questions. (a) Is it possible to calculate the torque acting on a rigid object without specifying an axis of rotation? (b) Is the torque independent of the location of the axis of rotation?
What three factors affect the torque created by a force relative to a specific pivot point?
What force must be applied to end of a rod along the x-axis of length 2.0 m in order to produce a torque on the rod about the origin of 8.0k Nm ?
An automobile engine can produce 200Nm of torque. Calculate the angular acceleration produced if 95.0 of this torque is applied to the drive shaft, axle, and rear wheels of a car, given the following information. The car is suspended so that the wheels can turn freely. Each wheel acts like a 15.0-kg disk that has a 0.180-m radius. The walls of each tire act like a 2.00-kg annular ring that has inside radius of 0.180 m and outside radius of 0.320 m. The tread of each tire acts like a 10.0-kg hoop of radius 0.330 m. The 14.0-kg axle acts like a rod that has a 2.00-cm radius. The 30.0-kg drive shaft acts like a rod that has a 3.20-cm radius.
A constant net torque is applied to an object. Which one of the following will not be constant? (a) angular acceleration, (b) angular velocity, (c) moment of inertia, or (d) center of gravity.
A constant torque is applied to a rigid body whose moment of inertia is 4.0kgm2 around the axis of rotation. If the wheel starts from rest and attains an angular velocity of 20.0 rad/s in 10.0 s, what is the applied torque?
A rod 7.0 m long is pivoted at a point 2.0 m from the left end. A downward force of 50 N acts at the left end, and a downward force of 200 N acts at the right end. At what distance to the right of the pivot can a third force of 300 N acting upward be placed to produce rotational equilibrium? Note: Neglect the weight of the rod. (a) 1.0 m (b) 2.0 m (c) 3.0 m (d) 4.0 m (e) 3.5 m
Can a set of forces have a net torque that is zero and a net force that is not zero?
The hour hand and the minute hand of Big Ben, the Parliament tower clock in London, are 2.70 m and 4.50 m long and have masses of 60.0 kg and 100 kg, respectively (see Fig. P10.17). (a) Determine the total torque due to the weight of these hands about the axis of rotation when the time reads (i) 3:00, (ii) 5:15, (iii) 6:00, (iv) 8:20, and (v) 9:45. (You may model the hands as long, thin, uniform rods.) (b) Determine all times when the total torque about the axis of rotation is zero. Determine the times to the nearest second, solving a transcendental equation numerically.
Problems 11 and 12 are paired. A thin disk of radius R has a nonuniform density = 4.5r2, when r is in meters. Derive an expression for the rotational inertia of this disk around an axis through its center and perpendicular to the disks surface, assuming R is given in meters.
A uniform cylindrical grinding wheel of mass 50.0 kg and diameter 1.0 m is turned on by an electric motor. The friction in the bearings is negligible. (a) What torque must be applied to the wheel to bring it from rest to 120 rev/min in 20 revolutions? (b) A tool whose coefficent of kinetic friction with the wheel with a force of 40.0 N. What torque must be supplied by the motor to keep the wheel rotating at a constant angular velocity?
Assume a single 300-N force is exerted on a bicycle frame as shown in Figure OQ10.5. Consider the torque produced by this force about axes perpendicular to the plane of the paper and through each of the points A through E, where E is the center of mass of the frame. Rank the torques A, B, C, D, and E from largest to smallest, noting that zero is greater than a negative quantity. If two torques are equal, note their equality in your ranking. Figure OQ10.5