Question
A wheel, originally rotating at 126 rad/s undergoes a angular of 5.00 rad/s^2. What is its angular speed has through an angle of 628 radians? A) 15 rad/s B) 19 rad/s C) 98 rad/s D) 121 rad/s E) 150 rad/s A wrench is used to tighten a as shown in the figure. A 12-N force is applied 7.0 cm from the axis of rotation. What is the magnitude of the torque due to the applied force? A) 0.58 N middot m B) 0.84 N middot m C) 1.71 N middot m D) 14 N middot m E) 58 N middot m A block is suspended from the ceiling by a long, thin strip of tungsten metal. The strip behaves as a spring. To produce a 0.25 m horizontal deflection of the block, a force of 6.5 N is required. Calculate the spring constant for the tungsten strip. A) 0.038 N/m B) 1.2 N/m C) 1.6 N/m D) 13 N/m E) 26 N/m
Explanation / Answer
here,
20)
the initial angular speed , w0 = 126 rad/s
accelration , alpha = - 5 rad/s^2
theta = 628 radians
let the final angular speed be w
using third equation
w^2 - w0^2 = 2 * alpha * theta
w^2 - 126^2 = 2 * (-5) * 628
w = 98 rad/s
the angular speed is c) 98 rad/s