KIN 44S Exam II Review Worksheet Quantity Symbol Unit Symbol Unit (Linear) (Linear) (Angular) (Angular) Dis - lac ement Acceleration Time Impulse Kinetic Energy Work Power 1. A pitched ball with a mass of 1 kg reaches the catcher's glove travelling at a velocity of 28 m/s. a. How much momentum does the ball have? b. How much impulse is required to stop the ball? c. If the ball is in contact with the catcher's glove for 0.5 5 during the catch, how much average force is applied by the glove? 2. A 3kg shot put is dropped from a height of 2 m. What is its momentum: a. Halfway to the ground? b. Just before it hits the ground? 3. What is the linear momentum of a 1.8 m tall 134 kg basketball player landing from a dunk at 3.1 mfs? 4. A 45 kg diver is in a layout position, with a radius of gyration of 0.40 m. She leaves the springboard with an angular velocity of 7 rad/s. What is the diver's angular velocity when she assumes a tuck position, reducing her radius of gyration to 0.21 m? 5. Luis is lifting a 10kg dumbbell by pulling upward on it with a 108.1 N force. What is the acceleration of the dumbbell as a result of this force? 6. Blanche, a 100 kg shot-putter, is putting the 4 kg shot in a track meet. Just before she releases the shot, Blanche is in the air (her feet are off the ground). At this instant, the only force she exerts against the shot is an 800 N horizontal force directed forward. a. What is Blanche's horizontal acceleration at this instant? b. What is Blanche's vertical acceleration at this instant? c. What is the shot's horizontal acceleration at this instant? d. What is the shot's vertical acceleration at this instant? 7. Calculate the height of the center of mass above its starting height during a squat jump based on the following information: BW= 670 N, total vertical ground reaction force: 788 N, time of force application: 095. 8. A 75 kg jumper lands stiff-legged on the oor and changes his velocity from -4.5 m/s t0 0 mfs in 0.15 seconds. Calculate the average ground reaction force under his feet during this time interval. (Remember net force and ground reaction force are not the same thing!) a. If the jumper lands with a softer landing and increases the impact time to 0.2 s, What is the average ground reaction force? 9. A force of 213 N is exerted a perpendicular distance of 0.25 m from the axis of rotation. What is the resulting moment of force? 10. Calculate the torque: 0.3 m 59 300 N a. 57 N 3.7 m b. 015m 125'\" 75N C. 11. An object has a moment of inertia of 150 kg*m2. A torque of 72 Nm is applied to the object. What is the angular acceleration? 12. A force of 200 N is applied at a point 1.3m perpendicularly from the axis of rotation, causing a revolving door to accelerate at 6.2 rad/52. What is the moment of inertia of the door? 13. How much torque must be generated by the deltoid muscle to hold a 60N dumbbell straight out at 90 degrees of shoulder abduction? What force must be generated to create this torque? The dumbbell is 0.6m from the shoulder joint. The center of mass of the arm, weighing 30 N, is 0.25m from the shoulder joint. The moment arm for the deltoid muscle is 0.05m. 14. Examine the diagram below. Using the information from the table, calculate the following values: a. Torque produced at the shoulder when the suitcase is held next to the thigh. b. Torque produced at the shoulder when the suitcase is held away from the body. Assume that the suitcase is bein held still in both ositions and in line with the hand's center of mass (COM). Segment Length gem! Mass {kg} Distance of segment COM to shoulder {cm} Upper arm 32 2.0 15 Forearm 30 1.2 42 Hand 17 0.8 67 Suitcase = 3kg hand forearm upper-arm T To I Shoulder inint Free body diagram /\\ 6 / 'IO 15. Doug is driving a golf ball off the tee. His downswing takes 0.505 from the top of the swing until ball impact. At the top of the swing, the club's angular velocity is zero; at the instant of ball impact, the club's angular velocity is 30 rad/5' The swing moment of inertia of the club about the grip is 0.220 kg*m2. The distance from the clubhead to the axis of rotation is 1.3m. a. What average torque does Doug exert on the golf club during the downswing? b. What is the linear velocity of the clubhead at impact? c. What is the centripetal acceleration of the clubhead at impact? 16. Sarah's twist angular momentum increases from 0 to 50 Nms in 0.255 as she initiates a twisting jump on the ice. During this 0.25s, her moment of inertia about her twist axis is 2.2 kg*m2. a. How large is the average torque that produces this change in angular momentum? b. How fast is Sarah's twist angular velocity at the end of the 0.255? 17. A champion hammer thrower rotates with a velocity of 11520/s just prior to releasing the hammer. The hammer is located 1.6m away from the axis of rotation. a. What is the centripetal acceleration experienced by the athlete? b. How much force is needed to produce this acceleration if the mass of the hammer is 7.3 kg? 18. By considering the conservation of energy, what velocity will at 80 kg diver have just before entering the water if he jumps from a 7m platform? 19. Jon snatched 100 kg. In a snatch, the barbell is moved from a stationary position on the oor to a stationary position over the athlete's head. Only 0.5s elapsed from the rst movement of the barbell until it was overhead, and the barbell moved through a vertical displacement of 2.0m. What was Jon's average power output during the lift? 20. Mike Adamle used to be a professional football player before becoming a host on American Gladiators, commentator on NBC, and commentator and on-screen General manager in the WWE. Adamle performs a swan dive (video available on Canvas!) from the 10m platform. If his mass is 77kg, calculate: a. Time of descent b. Potential energy of Adamle at the top of the platform c. Velocity of Adamle at water contact d. Force of Adamle at impact e. Work done by Adamle during his dive f. Impulse Adamle generated at water contact 10