10. A block (mass 2.00 kg) slides down a ramp, starting from rest at the top of the ramp (point A). At point B, at the bottom of the ramp 4.00 m vertically below point A, the speed of the block is 7.00 m/s. How much work did friction do on the block during its motion from A to B?
(a) +29.4 J
(b) -29.4 J
(c) +78.4 J
(d) -78.4 J
(e) +127 J
(f) -127 J
(g) none of the above answers
11. A small rock (mass 0.0500 kg) is thrown from the roof of a building, 20.0 m above the ground, with a speed of 15.0 m/s at an angle of 53.1 degrees about the horizontal. What is the speed of the rock just before it strikes the ground? Neglect air resistance.
(a) 24.8 m/s
(b) 19.8 m/s
(c) 12.9 m/s
(d) 3.9 m/l
(e) none of the above answers
12. A small rock (mass 0.0500 kg) is thrown from the ground with an initial speed of 20.0 m/s at an angle of 53.1° above the horizontal. What maximum height does the rock reach above the ground? Neglect air resistance.
(a) 6.5 m
(b) 13.0 m
(c) 20.4 m
(d) 26.8 m
(e) none of the above answers
13. A small block (0.200 kg) is on a horizontal surface and is placed at rest against a horizontal compressed spring that has 4.00 J of elastic potential energy stored in it. The spring is released and the block moves along the surface, leaving the spring behind. The coefficient of kinetic friction between the block and the surface is 0.300. How far does the block move before coming to rest?
(a) 1.4 m
(b) 2.0 m
(c) 5.4 m
(d) 6.8 m
(e) none of the above answers