Chapter 5 Review Physics 11 1. What is the distance between a 128 kg object and a 136 kg object if the gravitational force of attraction between them is 6.582x10-10 N? 2. The force of gravity between two objects is 1200 N when the objects are 60 m apart. Find the force of gravity between the objects when they are 480 m apart. 3. Two students are on a skateboards and push away from each other. A 48 kg student accelerates away at 2.6 m/s2. Find the acceleration of the other student if their mass is 32 kg. 4. A 42.0 N force is applied to a 6.00 kg block but it only accelerates at 5.50 m/s2. Determine both the force and the coefficient of friction. 5. A go-cart, traveling at 65 km/h, skids to a stop. If the coefficient of friction between the tires and the asphalt is 0.59, how far does the go-cart skid? 6. What is the size of the normal force from the floor of an elevator on a rider whose weight is 490 N if the elevator accelerates up at a rate of 0.650 m/s2? 7. A 2.5 kg and 3.6 kg mass are hung on either side of pulley and released. Find the acceleration of the larger mass, and the tension in the string. 8. What is the force applied to a 17.0 kg object that changes its velocity from 18.0 m/s to –38.5 m/s in a time of 14.0 s? 9. An 800 kg Volkswagen bug traveling at 6.4 m/s [E] bumps into a 5400 kg dump truck that is traveling at 2.8 m/s [W]. If the speed of the Volkswagen after the collision is 3.5 m/s [W], what is the final velocity of the dump truck? 10. What is the final velocity of a 28.0 kg object that has an initial velocity of 12.5 m/s and an applied force of 98.0 N as it slides for 6.80 s across a rough floor where µ=0.480 ? 11. A 490 kg grand piano is suspended on the end of a 2.35 m (rest length) spring. If the spring constant is 595 N/m, what is the extended length of the spring? Answers: 1. 3. 5. 7. 9. 11. d = 42.0 m a = -3.9 m/s2 d = 28.2 m a = 1.77 m/s2 [up], T = 28.9 N v = 1.3 m/s [ W ] l = 10.42 m 2. 4. 6. 8. 10. F = 18.8 N F = 9.0 N , µ = 0.153 F = 523 N F = -68.6 N v = 4.31 m/s