Physics Rotational Mechanics Level: High School
At a time t , a point on the rim of a wheel with a radius of ‘r’ has a tangential speed of ‘v’ as the wheel slows down with a tangential acceleration of constant magnitude a .a) Calculate the wheel’s constant angular acceleration .
b) Calculate the angular velocity at ‘t’ .
c) Calculate the angular velocity at ‘t = 0’.
d) Through what did the wheel turn between ‘t = 0’ and ‘t’ ?
e) At what time will the radial acceleration equal ‘g’ ?
Physics Rotational Mechanics Level: High School
A high-speed flywheel in a motor is spinning at 440 rpm when a power suddenly occurs . The flywheel has mass 38.0 kg and diameter 80.0 cm . The power is off for 27.0 s and during this time the flywheel slows due to friction in the axle bearings. Determine the time the power is off , the flywheel makes 160 complete revolutions .a) At what rate is flywheel spinning when the power comes back on ?
b) How long after the beginning of the power failure would it have taken the flywheel to stop if the power had not come back on ?
c) How many revolutions would the wheel have made during this time ?
Physics Rotational Mechanics Level: High School
Kinetic energy of a Rotating Wheel
A simple wheel has the form of a solid cylinder of radius with a mass m uniformly distributed throughout its volume . The wheel is pivoted on a stationary axle through the axis of the cylinder and rotates about the axle at a constant angular speed . The wheel rotates “full revolutions in a time interval”What is the kinetic energy K of the rotating wheel ?
Physics Rotational Mechanics Level: High School
A rope is wrapped around a large wheel that rotates on frictionless bearings through its center and a 2.00 kg mass is attached . The wheel is released and the mass falls a distance of 3.20 meters in a time of 2.50 seconds . The wheel has a radius of .600 meters . What is its moment of inertia ? (The mass hangs from the right side of the wheel ) .
Physics Rotational Mechanics Level: High School
A uniform circular disk has a mass of 12.0 kg and a radius of 30.0 cm . If a constant force of 5.00 N is applied tangential to its edge , what kinetic energy will it have after 30.0 seconds ? Consider the disk a solid cylinder .
Physics Rotational Mechanics Level: High School
Conservation of Angular Momentum
While a merry-go-round rotates at 2.51 rad / s , a child of mass 20.0 kg jumps on the outer edge . The merry-go-round has a mass of 32.0 kg and a radius of 1.00 m . What is the angular speed of the merry go round after child lands ? The child walks halfway toward the center . What is the merry-go-round’s new angular speed ?
Physics Rotational Mechanics Level: High School
Work in Rotational Motion
A solid desk of uniform mass 3.00 kg and diameter 50.0 cm rotates at a rate of 90 rpm . How much work is required to bring it to rest ? If the desk rotates through 4.00 revolutions while coming to rest , how much torque would bring it to rest ?
Physics Rotational Mechanics Level: High School
Rotational Equilibrium
A painter of mass 85.0 kg is on a scaffolding with uniform mass 15.0 kg and length 4.00 m . The scaffolding is suspended by ropes at both ends . If the painter stands 1.20 m from one end , what are the tensions in the two ropes at both end ? Also , if the painter stands at an end of the scaffolding , what are the 2 tensions ?
Physics Rotational Mechanics Level: High School
Equation of Rotational Motion
The blades of a fan run at a low speed at 180.0 rpm . When the fan switches to high speed , the rate of rotation of the blades increases uniformly to 240.0 rpm in 3.14 s . Through how many revolution do the blades go while they are accelerating ?
Physics Rotational Mechanics Level: High School
A figure skater is spinning at a rate of 1.4 rev / s with her arms outstretched . She then draws her arms in to her chest reducing her rotational inertial to 64% of its original value . What is her new rate of rotation ?
Physics Rotational Mechanics Level: High School
A skater is initially spinning at a rate of 13.0 rad/s with a rotational inertia of 2.55 kg m^2 when her arms are extended . What is her angular velocity after she pulls her arms in and reduce her rotational inertia to 1.62 kg m^2 ?
Physics Rotational Mechanics Level: High School
A turntable of mass 4.98 kg has a radius of 0.090 m and spins with a frequency of 0.501 rev/s . What is its angular momentum ? Assume the turntable is a uniform disk .
Physics Rotational Mechanics Level: High School
Rotational Equilibrium
In the moving Terminator , Arnold Schwarzengger lifts someone up by the neck and , with both arms fully extended and horizontal , holds the person off the ground . If the person being held weighs 610 N , is 60 cm from the shoulder joint , and Arnold has a anatomy analogous . What force must each of the deltoid muscles exert to perform this task ? [Hint : The weight of the arm is 30.0 N and its center of gravity is at the elbow joint , 27.5 cm from the shoulder joint]
Physics Rotational Mechanics Level: High School
Rotational Equilibrium
A uniform diving board , of length 5.0 m and mass 55 kg , is supported at two points ; one support is located 3.4 m from the end of the board and the second is at 4.6 m from the end . What are the forces acting on the board due to the two supports when a diver of mass 63 kg stands at the end of the board over the water ? Assume that these forces are vertical . [Hint : In this problem , consider using two different torque equations about different rotation axes . This may help you determine the directions of the two forces ] .
Physics Rotational Mechanics Level: High School
Rotational Equilibrium
A rod is being used as a lever . The fulcrum is 1.2 m from the load and 2.4 m from the applied force . If the load has a mass of 11.6 kg , what magnitude force must be applied to lift the load ?