Almaseera School Physics – 11A Ms. Fatima Alketbi 6.7) Non- conservative force and work – energy theorem 1 A 30.0-kg crate is pushed across a rough floor by a horizontal force of 100 N. The coefficient of kinetic friction between the crate and the floor is 0.100. If a total of 80.5 J of work is done on the crate, how far was it moved along the floor? A. 0.840 m B. 1.14 m C. 1.64 m D. 2.04 m E. 2.44 m 2 An 80-kg fireman slides down a 3-meter pole by applying a frictional force against the pole using his hands. If he slides from rest and he land on the ground with a speed of 6.00 m/s, the frictional force his hands applied against the pole was A. 423 N. B. 581 N. C. 735 N. D. 305 N. E. 912 N 3 A 3-kg block slides down a smooth incline of length 2 m inclined at 30 and hits a level, horizontal rough patch, coming to a stop in 1 m. What is the coefficient of friction between the block and the rough patch? A. B. C. D. E. 0.25 0.5 0.33 1.0 0.75 4 A 5-kg block of ice travels with a speed of 12 m/s when it hits a 25 incline plane. How far does it travel frictionlessly up the plane? A. 12.3 m B. 7.3 m C. 5.6 m D. 13.7 m E. 17.4 m Almaseera School Physics – 11A Ms. Fatima Alketbi 5 A tennis ball of mass 70 g is thrown vertically upward at 25 m/s. It rises to a height of 21 m. The work done by the resistive forces is A. -18.1 J. B. -7.5 J. C. -6.2 J. D. -3.5 J. 6 A 5.0-kg pumpkin is dropped from the top of the RCA Building in New York City. If it falls through a distance of 380 m, and splats on the sidewalk with a speed of 52.0 m/s, what is the work done by air resistance during its fall? A. 12 kJ B. -12 kJ C. 19 kJ D. -19 kJ 7 How much mechanical energy is lost to friction if a 22-kg box slides 7.0 m down a rough inclined plane at a constant speed of 11 m/s? The inclined plane makes an angle of 33 degrees with respect to the horizontal. A. 820 J B. 920 J C. 1300 J D. 1500 J E. 1700 J 8 I push an object along a horizontal surface a distance d with a force F at an angle A. B. C. D. E. . If the velocity is constant at a value v, then there is no net work done. the net work done is Fdcos . the net work done is Fdsin . you cannot calculate the net work. the net work done is Fv.