Register
A particle of mass m is attached to an inextensible massless string, and moves on the horizontal surface of a frictionless tabletop. The other end of the string passes through a hole in the tabletop, and
74.8k views
13 votes
A particle of mass m is attached to an inextensible massless string, and moves on the horizontal surface of a frictionless tabletop. The other end of the string passes through a hole in the tabletop, and is held taut by me. Initially the particle is moving in a circle with radius r0 and angular speed !0. I start to pull the string through the hole at a steady rate. Answer the following questions: a) Of kinetic energy and angular momentum, which one is conserved and which one is not? Explain how the tension force on the particle acts to change one but not the other

User John Zwarthoed
by
5.4k points

1 Answer

7 votes

Answer:

KE is not conserved because it takes work to pull on the string

(KE is a scalar and not a vector quantity)

Momentum is conserved because any force acting on the particle is perpendicular to its direction of motion

User Enchantres
by
5.1k points
Ask a Question
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

5.1m questions

6.7m answers

Other Questions

A space shuttle is approaching the surface of the moon to land. It approaches the moons surface with an initial velocity of 28m/s and is slowing at a rate of -2m/s^2. Show all work and units for problems.
5. What happens to the arrangement of water molecules as ice melts? A Molecules gain enough energy to escape as vapor. B Molecules release enough energy to escape as vapor. C Molecules gain enough energy
A projectline is shot from the edge of a cliff 100 m above the ground with intial speed 10 m/s at an angle 30 with the horizontal. 1) determine the time taken by the projectile motion to hit the ground
A 2.0-N force acts horizontally on a 10-N block that is initially at rest on a horizontal surface. The coefficient of static friction between the block and the surface is 0.50. Suppose that the block now
You’re on a team performing a high-magnetic-field experiment. A conducting bar carrying 4.1 kA will pass through a 1.3-m-long region containing a 12-T magnetic field, making a 60° angle with the field.
Link Copied!