A block with mass m= 14 kg rests on a frictionless table and is accelerated by a spring with spring constant k= 4067 N/m after being compressed a distance x, - 0.544 m from the spring's unstretched length. The floor is frictionless except for a rough patch a distance d= 2.6 m long. For this rough path, the coefficient of friction is p, = 0.43. 1) How much work is done by the spring as it accelerates the block? 2) What is the speed of the block right after it leaves the spring? 3) How much work is done by friction as the block crosses the rough spot?

A bag of sand which acts as a counter weight for a stage set is suspended vertically by a rope of length L = 6.00 m and has a mass m = 132 kg. If a stagehand pushes the bag of sand a distance d = 5.00 m sideway: (a) the horizontal force needed in order to hold the bag at this position (b) the amount of work done on the bag by gravity as the stagehand pushes it to this position (Include the sign of the value in your answer.) (c) the amount of work done by the stagehand as he pushes the bag to this position (Include the sign of the value in your answer.)

In the figure, a block of mass m = 1.30 kg slides head on into a spring of spring constant k = 390 N/m. When the block stops, it has compressed the spring by 6.60 cm. The coefficient of kinetic friction between block and floor is 0.330. While the block is in contact with the spring and being brought to rest, what are (a) the work done by the spring force and (b) the increase in thermal energy of the block-floor system? (c) What is the block's speed just as the block reaches the spring?

A horizontal force of magnitude 37.4 N pushes a block of mass 3.83 kg across a floor where the coefficient of kinetic friction is 0.639. (a) How much work is done by that applied force on the block-floor system when the block slides through a displacement of 3.86 m across the floor? (b) During that displacement, the thermal energy of the block increases by 39.5 J. What is the increase in thermal energy of the floor? (c) What is the increase in the kinetic energy of the block? (a) Number Units (b) Number i Units (c) Number Units >