A 2.5-kg box, sliding on a rough horizontal surface, has a speed ...

[lindiwe]

A 2.5-kg box, sliding on a rough horizontal surface, has a speed of 1.2 m/s when it makes contact with a spring (see the figure).
 
  The block comes to a momentary halt when the compression of the spring is 5.0 cm. The work done by the friction, from the instant the block makes contact with the spring until is comes to a momentary halt, is -0.50 J.
 
  (a) What is the spring constant of the spring?
  (b) What is the coefficient of kinetic friction between the box and the rough surface?
  What will be an ideal response?

Question 2

A 1.86-kg block is held in place against the spring by a 81-N horizontal external force (see the figure). The external force is removed, and the block is projected with a velocity v1 = 1.2 m/s upon separation from the spring.
 
  The block descends a ramp and has a velocity at the bottom. The track is frictionless between points A and B. The block enters a rough section at B, extending to E. The coefficient of kinetic friction over this section is 0.28. The velocity of the block is v3 = 1.4 m/s at C. The block moves on to D, where it stops. The height h of the ramp is closest to
 
  A) 11
  B) 7.3
  C) 15
  D) 17
  E) 18

[jsm54321]

Answer to Question 1

Answer: (a) 1040 N/m (b) 0.41

Answer to Question 2

Answer: A

[lindiwe]

Thank you!

[jsm54321]

Always glad to help...