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 ?
Physics Rotational Mechanics Level: High School
A bicycle has wheels of radius 0.33 m . Each wheel has a rotational inertia of 0.081 kgm^2 about its axle . The total mass of the bicycle including the wheels and the rider is 71 kg . When coasting at constant speed , what fraction of the total kinetic energy of the bicycle (including rider) is the rotational kinetic energy of the wheels ?
Physics Rotational Mechanics Level: High School
Rotational Equilibrium
A 4.0 m wood plank of mass 100.0 kg is nailed to two supporting “horses” at each end . Two painters stand on the plank as shown in the diagram at “click here” . Assume the center of gravity is in the middle of the plank . Find the force acting down on the left and right “horses” .
Physics Rotational Mechanics Level: High School
Torque
The man in the diagram which is shown at “click here” is trying to bend the tree . He ties a rope to the tree at a point 5.6 m above the ground and pulls with a force of 65 N . He stands 4.0 m from the base of the tree . Find the bending torque on the tree . (Hint : use trig to get some angle ) .
Physics Rotational Mechanics Level: High School
What occurs when a torque is applied to an object that is free to rotate ?Physics Rotational Mechanics Level: High School
What’s the magnitude of the torque if a door is turned with 20 . N force applied 0.70 m from the door’s hinges ?
Physics Rotational Mechanics Level: High School
A solid disk of steel has a diameter of 0.600 m and a mass of 234 kg rolls horizontally without slipping at 1.5 m /s . Find its KE (total) in J , using the combined or alternative equation p.298 (eq. 10-20) .
Physics Rotational Mechanics Level: High School
A 250.g basketball of diameter 30.0 cm rolls slowly along the floor at 20.0 cm/s . Solve separately for its KE (linear) and KE (rotation) , both in J .
Physics Rotational Mechanics Level: High School
Use the data on the rear inside cover of your text to calculate the KE (rotation) of the earth on its axis . (Hint : get omega in radians / s knowing that earth rotates once in 24 hours )
Physics Rotational Mechanics Level: High School
Conservation of Angular Momentum
A skater spins at 6.0s^-1 with one leg and both arms stretched from her body so her effective I is 90 kg*m^2 . What will be her angular velocity when she pulls in her leg and arms to her sides making her effective I only 40. Kg*m^2 ? ?