H 6.9 3/3 points (graded) a. Calculate the work in kJ = 103 J done on a 1500-kg elevator car by its cable to lift it 50 m at constant speed, assuming friction averages 100 N. Give your answer to two significant figures without units. 740 b. What is the work in kJ = 103 J done on the elevator by the gravitational force in this process? Give your answer to two significant figures without units. -735 V c. What is the total work (or net work) in kJ = 10º J done on the elevator? Give your answer to two significant figures without units. 0 V Submit Show answer H 6.10 3/3 points (graded) A boy pulls a 7-kg cart with a 20-N force at an angle of 30° above the horizontal for a length of time. Over this time frame, the cart moves a distance of 14 m on the horizontal floor. a. Find the work ( in J ) done on the cart by the bov. Give your answer to two significant figures without units. 242.49 > b. What will be the work ( in J ) done by the boy if he pulled with the same force horizontally instead of at an angle of 30° above the horizontal over the same distance? Give your answer to two significant figures without units. 280 c. Solve part (a) assuming that now there is a friction between the cart and the horizontal surface. The coeeficient of kinetic friction is (4% = 0.01. Give your answer to two significant figures without units. 234.28 V