12. A trail maintenance team is using explosives to remove a 895 kg boulder from a trail. When the explosive charge is detonated, the boulder splits into two parts. The larger part has a mass of 515 kg, and moves west at a speed of 3.4 m/s. What is the velocity of the smaller part? 13. Janelle is tightening a bolt on her car, which requires her to twist the bolt clockwise. The wrench she is using has a length of 24 cm. If she pulls on the wrench handle with a force of 16N, what torque is she exerting on the bolt? Assume that her force is perpendicular to the wrench handle. 14. To help keep heating costs down, Richard installs a spring that connects the door to the doorframe, allowing the door to automatically close. When the door is opened to a certain distance, the spring exerts a 22 N force, with a lever arm of 41 cm. The angle between the force vector and lever arm is 64°. If this setup rotates the door counterclockwise, what is the torque vector exerted on the door? 15. A pulley system is set up to help lift a car off the ground. If the car has a mass of 1440 kg, and it requires a force of 4.75 kN to lift the car, what is the mechanical advantage of the pulley system? 16. Terrance uses a ramp to get sound equipment onto a 2.1 m stage. One speaker has a mass of 65 kg. In order to get this speaker up the ramp, Terrence has to push with a force of 290 N, over a distance of 6.4 m. What is the efficiency of this ramp?

Fig: 1