A kind of Atwood's machine is built from two cylinders of mass m1 and m2; a cylindrical pulley of mass m3 and radius r; a light, frictionless axle; and a piece of light, unstretchable string. The heavier mass m1 is held above the ground a height h and then relased from rest.
Draw a free body diagram showing all the forces acting on…
the heavier mass
the lighter mass
the pulley
Write the equation stating Newton's second law of translational motion for…
the heavier mass
the lighter mass
and rotational motion for…
the pulley
Determine the translational acceleration of…
the heavier mass
the lighter mass
and the rotational acceleration of…
the pulley
Determine the tension in the side of the string connected to
the heavier mass
the lighter mass
and the upward force of the axle on…
the pulley
Lastly, determine…
the time it takes for the heavier mass to reach the ground
its speed on impact
the rotational speed of the pulley at this time
A roll of toilet paper is held by the first piece and allowed to unfurl as shown in the diagram to the right. The roll has an outer radius R = 6.0 cm, an inner radius r = 1.8 cm, a mass m = 200 g, and falls a distance s = 3.0 m. Assuming the outer diameter of the roll does not change significantly during the fall, determine…
the tension in the sheets
the translational acceleration of the roll
the angular acceleration of the roll
the final translational speed of roll
the final angular speed of the roll
The top shown below consists of a cylindrical spindle of negligible mass attached to a conical base of mass m = 0.50 kg. The radius of the spindle is r = 1.2 cm and the radius of the cone is R = 10 cm. A string is wound around the spindle. The top is thrown forward with an initial speed of v0 = 10 m/s while at the same time the string is yanked backward. The top moves forward a distance s = 2.5 m, then stops and spins in place.
Using rotational dynamics (and kinematics) determine…
the moment of inertia I of the top (essentially, the moment of inertia of a cone)
the tension T in the string
the final angular velocity ω of the top
the length ℓ of string wound around the spindle
Write something different.
conceptual
Describe a test involving rotational principles that can be used to distinguish raw eggs from hard boiled eggs.
Some airplanes have only one propeller, but all helicopters have two rotors. (A helicopter with only one rotor is unflyable.)
Why must helicopters always have two rotors?
How does a single propeller aircraft manage to avoid the problems encountered by a single rotor helicopter?