| A | B |
|---|
| 1. A 60.0-kg speed skater with a velocity of 18.0 m/s comes into a curve of 20.0-m radius. How much friction must be exerted between the skates and ice to negotiate the curve? | 972 N |
| 2. A jet plane traveling 500 m/s pulls out of a dive by moving in an arc of radius 6 km. What is the plane's centripetal acceleration? | 41.7 m/s^2 |
| 3. A 25.0-kg child on a merry-go-round is moving with a speed of 1.35 m/s when 1.20 m from the center of the merry-go-round. Calculate the centripetal acceleration of the child and the net horizontal force exerted on the child. | 38 N |
| 4. A horizontal force of 280 N is exerted on a 2.0-kg discus as it is rotated uniformly in a circle of radius 1.00 m. Calculate the speed of the discus. | 11.8 m/s |
| 5. A 0.40-kg ball, attached to the end of a horizontal cord, is rotated in a circle of radius 1.3 m on a frictionless horizontal surface. If the cord will break when the tension exceeds 60 N, what is the maximum speed the ball can have? | 13.96 m/s |
| 6. What is the maximum speed with which a 1050-kg car can round a turn of radius 70 m on a flat road if the coefficient of friction between the tires and the road is 0.80? | 23.4 m/s |
| 7. How large must the coefficient of friction be between the tires and the road if a car is to round a level curve of 85 m at a speed of 95 km/h? | 0.84 |
| 8. Jessica is riding on a merry-go-round on an outer horse that sits at a distance of 8.0 m from the center of the ride. Jessica's sister, Julie, is in an inner horse located 6.0 m from the ride's center. The merry-go-round turns around once every 40 s. Calculate the speed and centripetal acceleration of each girl. | 0.20 m/s^2; 0.15 m/s^2 |
