1. By what factor does a cyclist's kinetic energy increase if the cyclist's speed: (a) Doubles (b) Triples (c) halved 2. An astronaut of mass 63 kg climbs a set of stairs with a total vertical rise of 3.4 m. (a)What is the astronaut's gravitational potential energy, relative to the bottom of the stairs, If the stairs are located on Earth? (b)Repeat (a) if the stairs are located on the Moon where g = 1.6 N/kg.3. (a) Spring A has a force constant of 68 N/m. Spring B has a force constant of 48 me. Which spring is harder to stretch? (b) What is the energy stored in each one when compressed by 40 cm. 4. A 45-g golf ball leaves the tee with a speed of 43 m/s after a golf club strikes it. (a) Determine the work done by the club on the ball. (b) Determine the magnitude of the average force applied by the club to the ball, assuming that the force is parallel to the motion of the ball and acts over a distance of 2.0 cm. 5. A delivery person pulls a 20.0-kg box across the floor. The force exerted on the box is IOON [37 above the horizontal]. The coefficient of kinetic friction with the floor is %The box starts from rest. Determine the speed of the box after being dragged 81 cm. 6. A 61-kg skier, coasting down a hill that is at an angle of 23 to the horizontal, experiences a force of kinetic friction of magnitude 72 N. The skier's speed is 3.5 m/s near the top ofthe slope. If the skier has travelled 62 n1 downhill, determine; a. The work done by force of gravity (Weight). The work done by force of friction. The NET Work done. The initial kinetic energy. The speed at the end of the 62 n1 downhill. Air resistance is negligible. gunpo- 7. A ball of mass 0.075 kg is hung from a vertical spring that is allowed to stretch slowly from its Wequilibrium position until it comes to a new equilibrium position 0.15 m below the initial one as shown in the Figure. la) Determine the force co tant of the spring. (b) If the ball is returned t he spring's Wequilibrium position and then allowed to fall, what is the net force on the ball when it has dropped 0.071 m? (c) Determine the acceleration of the ball at the position specified in (b). (d) How much elastic potential energyr is stored in the spring in part (a) I x- 0.15 m