1.There is no friction on the pulley\'s axle; the cord does not slip on the pull

Question

1.There is no friction on the pulley's axle; the cord does not slip on the pulley. What is the speed of the object after it has fallen a distance h = 0.7 m from rest: Use work - energy considerations.

2. Calculate the kinetic energies of two uniform solid cylinders, each rotating about its central axis. They have the same mass, 1.25 kg, and rotate with the same angular velocity, 195 rad/s, but the first has a radius of 0.25 m and the second a radius of 0.75 m. Kinetic energy of the first cylinder?

Kinetic energy of the second cylinder?

Explanation / Answer

if there is no friction

then the force acting here is only the gravitational force which is equal to the kinetic energy

so speed v= sqrt(2gs)

                   = sqrt(2*10*0.7)

                  = 3.74m/s

2) kinetic energy = 1/2 Iw2

                             = 1/2 mr2/2*w2

                            = 594 m   J    for first cylinder

for second cylinder = 5347 m   J

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.