2 Masses on a Pulley - Conservation of Energy Demonstration

The video tutorial explains a physics problem involving a frictionless pulley system with two masses. The problem is solved using the conservation of mechanical energy, focusing on the initial and final mechanical energies of the system. The tutorial guides through substituting equations to find the angular velocity and ultimately derive the angular acceleration of the pulley. The approach highlights the relationship between linear and angular motion, demonstrating that the problem can be solved using either energy conservation or Newton's laws.

What is the primary assumption made about the pulley in the problem?

• The pulley has significant friction.

• The pulley is frictionless at the axle.

• The pulley has a large radius.

• The pulley is not rotating.

Why is mechanical energy conserved in this system?

• Because there is no external force applied.

• Because the system is isolated in a vacuum.

• Because the masses are equal.

• Because the pulley is not moving.

What is the initial mechanical energy in the system?

• The elastic potential energy of a spring.

• The kinetic energy of mass 1.

• The rotational kinetic energy of the pulley.

• The gravitational potential energy of mass 2.

How is the final angular velocity of the pulley related to the linear velocities of the masses?

• It is twice the linear velocity.

• It is equal to the linear velocity divided by the radius.

• It is half of the linear velocity.

• It is unrelated to the linear velocity.

What equation is used to relate angular displacement to linear distance traveled by the masses?

• Arc length equals radius times angular displacement.

• Linear distance equals angular velocity times time.

• Radius equals arc length divided by time.

• Angular displacement equals mass times acceleration.

What is the final expression for the angular acceleration of the pulley?

• Pulley radius squared times the sum of masses.

• Pulley radius times the sum of masses divided by rotational inertia.

• Pulley radius times acceleration due to gravity times the difference in masses divided by the sum of masses and rotational inertia.

• Pulley radius times mass 1 divided by mass 2.

What alternative method can be used to solve the problem besides conservation of mechanical energy?

• Using the law of conservation of momentum.

• Using the translational and rotational forms of Newton's second law.

• Using the law of universal gravitation.

• Using the principle of least action.