An 8.0-m massless rod is loosely pinned to a frictionless pivot ...

[silviawilliams41]

An 8.0-m massless rod is loosely pinned to a frictionless pivot at 0, as shown in the figure. A very small 4.0-kg ball is attached to the other end of the rod.
 
  The ball is held at A, where the rod makes a 30 angle above the horizontal, and is released. The ball-rod assembly then swings freely with negligible friction in a vertical circle between A and B. The tension in the rod when the ball passes through the lowest point at D is closest to
 
  A) 160 N.
  B) 200 N.
  C) 120 N.
  D) 80 N.
  E) 40 N.

Question 2

A mass is pressed against (but is not attached to) an ideal horizontal spring on a frictionless horizontal surface. After being released from rest, the mass acquires a maximum speed v and a maximum kinetic energy K.
 
  If instead the mass initially compresses the spring twice as far:
  A) Its maximum speed will be 2v and its maximum kinetic energy will be 2K.
  B) Its maximum speed will be 2v and its maximum kinetic energy will be K.
  C) Its maximum speed will be v and its maximum kinetic energy will be 2K.
  D) Its maximum speed will be 2v and its maximum kinetic energy will be 4K.
  E) Its maximum speed will be 4v and its maximum kinetic energy will be 2K.

[Amiracle]

Answer to Question 1

Answer: A

Answer to Question 2

Answer: C

[silviawilliams41]

Both answers were spot on, thank you once again

[Amiracle]

Great! Please up vote