Multiple ChoiceA tiny object spins with 5 rad/s around a circular path of radius 10 m. The object then accelerates at 3 rad/s2. Calculate its angular speed 8 s after starting to accelerate.BONUS:Calculate its linear displacement in the 8 s.760views6rank2comments
Multiple ChoiceThe turntable of a DJ set is spinning at a constant rate just before it is turned off. If the turntable decelerates at 3 rad/s2 and goes through an additional 30 rotations before stopping, how fast (in RPM) was the turntable initially spinning? BONUS:How long (in seconds) does the turntable take to stop?811views4rank6comments
Textbook QuestionA high-speed flywheel in a motor is spinning at 500 rpm when a power failure suddenly occurs. The flywheel has mass 40.0 kg and diameter 75.0 cm. The power is off for 30.0 s, and during this time the flywheel slows due to friction in its axle bearings. During the time the power is off, the flywheel makes 200 complete revolutions. (a) At what rate is the flywheel spinning when the power comes back on?1107views
Textbook QuestionAn electric fan is turned off, and its angular velocity decreases uniformly from 500 rev/min to 200 rev/min in 4.00 s. (b) How many more seconds are required for the fan to come to rest if the angular acceleration remains constant at the value calculated in part (a)?1723views
Textbook QuestionAn electric fan is turned off, and its angular velocity decreases uniformly from 500 rev/min to 200 rev/min in 4.00 s. (a) Find the angular acceleration in rev/s^2 and the number of revolutions made by the motor in the 4.00-s interval. (b) How many more seconds are required for the fan to come to rest if the angular acceleration remains constant at the value calculated in part (a)?897views
Textbook QuestionA wheel is rotating about an axis that is in the z-direction. The angular velocity ω_z is -6.00 rad/s at t = 0, increases linearly with time, and is +4.00 rad/s at t = 7.00 s. We have taken counterclockwise rotation to be positive. (c) What is the angular displacement of the wheel at t = 7.00 s?609views
Textbook QuestionA wheel is rotating about an axis that is in the z-direction. The angular velocity ω_z is -6.00 rad/s at t = 0, increases linearly with time, and is +4.00 rad/s at t = 7.00 s. We have taken counterclockwise rotation to be positive. (a) Is the angular acceleration during this time interval positive or negative?1063views
Textbook QuestionAn electric turntable 0.750 m in diameter is rotating about a fixed axis with an initial angular velocity of 0.250 rev/s and a constant angular acceleration of 0.900 rev/s^2. (a) Compute the angular velocity of the turntable after 0.200 s. (b) Through how many revolutions has the turntable spun in this time interval?663views
Textbook QuestionA wheel is rotating about an axis that is in the z-direction. The angular velocity ω_z is -6.00 rad/s at t = 0, increases linearly with time, and is +4.00 rad/s at t = 7.00 s. We have taken counterclockwise rotation to be positive. (b) During what time interval is the speed of the wheel increasing? Decreasing?303views
Textbook QuestionA wheel of diameter 40.0 cm starts from rest and rotates with a constant angular acceleration of 3.00 rad/s^2. Compute the radial acceleration of a point on the rim for the instant the wheel completes its second revolution from the relationship (a) a_rad = ω^2r and (b) a_rad = v^2/r418views
Textbook Question(I) Pilots can be tested for the stresses of flying high-speed jets in a whirling “human centrifuge,” which takes 1.0 min to turn through 26 complete revolutions before reaching its final speed.(a) What was its angular acceleration (assumed constant)?147views
Textbook Question(II) Assume that a 1.00-kg ball is thrown solely by the action of the forearm, which rotates about the elbow joint under the action of the triceps muscle, Fig. 10–57. The ball is accelerated uniformly from rest to 8.5 m/s in 0.38 s, at which point it is released. Calculate(a) the angular acceleration of the arm, and<IMAGE>109views
Textbook Question(I) The blades in a blender rotate at a rate of 8500 rpm (rpm = revolutions per minute = rev/min) . When the motor is turned off during operation, the blades slow to rest in 4.0 s. What is the angular acceleration as the blades slow down?156views
Textbook QuestionAn 18-cm-long bicycle crank arm, with a pedal at one end, is attached to a 20-cm-diameter sprocket, the toothed disk around which the chain moves. A cyclist riding this bike increases her pedaling rate from 60 rpm to 90 rpm in 10 s. What is the tangential acceleration of a tooth on the sprocket?369views1rank
Textbook QuestionA ceiling fan with 80-cm-diameter blades is turning at 60 rpm. Suppose the fan coasts to a stop 25 s after being turned off. (b) Through how many revolutions does the fan turn while stopping?876views
Textbook QuestionA ceiling fan with 80-cm-diameter blades is turning at 60 rpm. Suppose the fan coasts to a stop 25 s after being turned off. (a) What is the speed of the tip of a blade 10 s after the fan is turned off?330views
Textbook QuestionA high-speed drill reaches 2000 rpm in 0.50 s. (a) What is the magnitude of the drill's angular acceleration?305views
Textbook QuestionThe 2.0 kg, 30-cm-diameter disk in FIGURE P12.65 is spinning at 300 rpm. How much friction force must the brake apply to the rim to bring the disk to a halt in 3.0 s?254views
Textbook Question(I) Pilots can be tested for the stresses of flying high-speed jets in a whirling “human centrifuge,” which takes 1.0 min to turn through 26 complete revolutions before reaching its final speed.(b) what was its final angular speed in rpm?157views
Textbook Question(II) A cooling fan is turned off when it is running at 780 rev/min . It turns 1250 revolutions before it comes to a stop. (b) How long did it take the fan to come to a complete stop?160views
Textbook Question(II) Calculate the average angular velocity of a clock’s second hand, its minute hand, and its hour hand. State in rad/s . (d) What is the average angular acceleration in each case?169views
Textbook Question(II) Calculate the angular velocity of the Earth (a) in its orbit around the Sun, and (b) about its axis.154views
Textbook QuestionA bicycle wheel has an initial angular velocity of 1.50 rad/s. (a) If its angular acceleration is constant and equal to 0.200 rad/s^2, what is its angular velocity at t = 2.50 s? (b) Through what angle has the wheel turned between t = 0 and t = 2.50 s?68views