/*Start of Problem*/
/*Problem Num*/Problem #16
/*Difficulty*/2
/*Picture URL*/4.1f.svg
/*FBD URL*/FBD1.svg
/*Description*/The ladder is propped up against the wall.
/*Object List*/ E=Earth, L=Ladder, W=Wall
/*Systems*/
/*Strings*/
/*Springs and spring status*/
/*FBD List*/L
/*Relative Motions*/L left E, L down W
/*Frictionless Surfaces*/
/*Accelerations*/
/*End of Problem*/ 

/*Start of Problem*/
/*Problem Num*/Problem #19
/*Difficulty*/2
/*Picture URL*/4.2d.svg
/*FBD URL*/FBD2.svg
/*Description*/A car is driving to the right when the brakes are applied.  A pendulum inside of the car swings forward.
/*Object List*/ E=Earth, S=String, B=Bob, C=Car, P=Pendulum
/*Systems*/P=S+B
/*Strings*/S
/*Springs and spring status*/
/*FBD List*/C, P
/*Relative Motions*/C right E
/*Frictionless Surfaces*/
/*Accelerations*/
/*End of Problem*/ 

/*Start of Problem*/
/*Problem Num*/Problem #22
/*Difficulty*/2
/*Picture URL*/4.2e.svg
/*FBD URL*/FBD2.svg
/*Description*/The yellow block slows down while sliding down the incline.
/*Object List*/E=Earth, Y=Yellow Block, B=Blue Block, 1=First Part of String, 2=Second Part of String, P=Pulley, S=String
/*Systems*/S=1+2
/*Strings*/1, 2
/*Springs and spring status*/
/*FBD List*/Y, B
/*Relative Motions*/Y down E
/*Frictionless Surfaces*/
/*Accelerations*/Y upright, B down
/*End of Problem*/ 

/*Start of Problem*/
/*Problem Num*/Problem #28
/*Difficulty*/3
/*Picture URL*/4.3c.svg
/*FBD URL*/FBD3.svg
/*Description*/Two blocks speed up as they slide together to the right when a hand pushes the top block horizontally.<br><br>This problem is identical to the last except the blocks in this problem speed up instead of moving at constant speed.  Notice the button that allows you to copy the forces from your previous answer if you choose.  In addition, be aware that you can also go back to the previous problem and look at your answer if that would be helpful.  
/*Object List*/ E=Earth, Y=Yellow Block, B=Blue Block, H=Hand, S=Two Block System
/*Contact Forces*/HY 0 horizontally
/*Systems*/S=Y+B
/*Strings*/
/*Springs and spring status*/
/*FBD List*/Y, B, S
/*Relative Motions*/Y zero B, B right E
/*Frictionless Surfaces*/
/*Accelerations*/B zero
/*Paired With Previous Problem*/-1
/*End of Problem*/ 

/*Start of Problem*/
/*Problem Num*/Problem #29
/*Difficulty*/3
/*Picture URL*/4.4a.svg
/*FBD URL*/FBD3.svg
/*Description*/A block sits on top of a wedge.  They speed up as they slide down the sloped surface of the earth but do not move relative to each other. 
/*Object List*/ E=Earth, Y=Yellow Block, B=Blue Wedge, S=Wedge & Block System
/*Systems*/S=Y+B
/*Strings*/
/*Springs and spring status*/
/*FBD List*/Y, B, S
/*Relative Motions*/Y zero B, B down E
/*Frictionless Surfaces*/
/*Accelerations*/B downright
/*End of Problem*/ 

/*Start of Problem*/
/*Problem Num*/Problem #23
/*Difficulty*/3
/*Picture URL*/4.2f.svg
/*FBD URL*/FBD3.svg
/*Description*/The block slides up the ramp which remains stationary.
/*Object List*/ E=Earth, Y=Yellow Block, B=Blue Wedge, S=Block & Wedge System
/*Systems*/S=Y+B
/*Strings*/
/*Springs and spring status*/
/*FBD List*/Y, B, S
/*Relative Motions*/Y up B
/*Frictionless Surfaces*/
/*Accelerations*/B zero
/*End of Problem*/ 

/*Start of Problem*/
/*Problem Num*/Problem #23
/*Difficulty*/3
/*Picture URL*/4.2l.svg
/*FBD URL*/FBD3.svg
/*Description*/The block sits at rest on a wedge which is also stationary.  There is no friction between the block and wedge.  The block is held at rest by a string.<br><br>This problem is similar to the previous problem (i.e., problem #22) except this time the block is held at rest by a string instead of friction.  Notice the 'Copy Answers from Previous Problem' button that allows you to copy the forces from your previous answer if you choose.  In addition, be aware that you can use the 'Next Problem' and 'Previous Problem' buttons to look at your previous answers if that would be helpful.
/*Object List*/ E=Earth, Y=Yellow Block, B=Blue Wedge, P=String, S=Block & Wedge System
/*Systems*/S=Y+B+P
/*Strings*/P
/*Springs and spring status*/
/*FBD List*/Y, B, S
/*Relative Motions*/Y zero B, B zero E
/*Frictionless Surfaces*/Y B
/*Accelerations*/Y zero, B zero
/*Paired With Previous Problem*/-1
/*End of Problem*/ 

/*Start of Problem*/
/*Problem Num*/Problem #29
/*Difficulty*/3
/*Picture URL*/4.3e.svg
/*FBD URL*/FBD3.svg
/*Description*/Two blocks move to the right when a hand pushes the yellow block horizontally.  Assume that the hand pushes hard enough so that the yellow block does not fall.  
/*Object List*/ E=Earth, Y=Yellow Block, B=Blue Block, H=Hand, S=Two Block System
/*Contact Forces*/HY 0 horizontally
/*Systems*/S=Y+B
/*Strings*/
/*Springs and spring status*/
/*FBD List*/Y, B, S
/*Relative Motions*/Y zero B, B right E
/*Frictionless Surfaces*/
/*Accelerations*/Y right
/*Summary*/
/*End of Problem*/ 

/*Start of Problem*/
/*Problem Num*/Problem #30
/*Difficulty*/3
/*Picture URL*/4.3f.svg
/*FBD URL*/FBD3.svg
/*Description*/Two blocks move to the right when a hand pushes the blue block horizontally.  Assume that the hand pushes hard enough so that the yellow block does not fall.  
/*Object List*/ E=Earth, Y=Yellow Block, B=Blue Block, H=Hand, S=Two Block System
/*Contact Forces*/HB 0 horizontally
/*Systems*/S=Y+B
/*Strings*/
/*Springs and spring status*/
/*FBD List*/Y, B, S
/*Relative Motions*/Y zero B, B right E
/*Frictionless Surfaces*/
/*Accelerations*/Y right
/*Summary*/
/*End of Problem*/ 

/*Start of Problem*/
/*Problem Num*/Problem #25
/*Difficulty*/2
/*Picture URL*/4.3a.svg
/*FBD URL*/FBD2.svg
/*Description*/The yellow block is hanging from a string which is attached to a beam.  The beam rests against a wall and is supported by a cable.  
/*Object List*/ E=Earth, Y=Yellow Block, B=Beam, S=String, C=Cable, W=Wall, P=Block & String System
/*Systems*/P=Y+S
/*Strings*/S, C
/*Springs and spring status*/
/*FBD List*/B, P
/*Relative Motions*/B down W
/*Frictionless Surfaces*/
/*Accelerations*/
/*Summary*/
/*End of Problem*/ 

UNSOLVABLE (Involves two unknown springs on the same object.)
/*Start of Problem*/
/*Problem Num*/Problem #16
/*Difficulty*/2
/*Picture URL*/4.1i.svg
/*FBD URL*/FBD1.svg
/*Description*/The block is attached to two springs and a string.  The block sits at rest.
/*Object List*/ E=Earth, B=Block, 1=First Spring, 2=Second Spring, S=String ,C=Ceiling, W=Wall
/*Systems*/
/*Strings*/S
/*Springs and spring status*/1 unknown, 2 unknown
/*FBD List*/B
/*Relative Motions*/
/*Frictionless Surfaces*/
/*Accelerations*/B zero
/*Paired With Previous Problem*/
/*Summary*/  
/*End of Problem*/