10. [2/6 Points] DETAILS PREVIOUS ANSWERS SERPSE10 4.4.P.020. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER An athlete swings a ball, connected to the end of a chain, in a horizontal circle. The athlete is able to rotate the ball at the rate of 8.45 rev/s when the length of the chain is 0.600 m. When he increases the length to 0.900 m, he is able to rotate the ball only 6.26 rev/s. (a) Which rate of rotation gives the greater speed for the ball? 0 6.26 rev/s 8.45 rev/s (b) What is the centripetal acceleration of the ball at 8.45 rev/s? X Your response differs significantly from the correct answer. Rework your solution from the beginning and check each step carefully. m/s (c) What is the centripetal acceleration at 6.26 rev/s? m/s2 Need Help? Read It Submit Answer12. [-/6 Points] DETAILS SERPSE10 4.5.OP.025.MI. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A train slows down as it rounds a sharp horizontal turn, going from 80.0 km/h to 44.0 km/h in the 12.0 s that it takes to round the bend. The radius of the curve is 160 m. Compute the acceleration at the moment the train speed reaches 44.0 km/h. Assume the train continues to slow down at this time at the same rate. magnitude m/s2 direction . backward (behind the radial line pointing inward) Need Help? Read It Master It Submit Answer8. [-/15 Points] DETAILS SERPSE10 4.3.OP.015. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Children playing in a playground on the flat roof of a city school lose their ball to the parking lot below. One of the teachers kicks the ball back up to the children as shown in the figure below. The playground is 5.90 m above the parking lot, and the school building's vertical wall is h = 7.20 m high, forming a 1.30 m high railing around the playground. The ball is launched at an angle of 0 = 53.0 above the horizontal at a point d = 24.0 m from the base of the building wall. The ball takes 2.20 s to reach a point vertically above the wall. (Due to the nature of this problem, do not use rounded intermediate values in your calculations-including answers submitted in WebAssign.) (a) Find the speed (in m/s) at which the ball was launched. m/s (b) Find the vertical distance (in m) by which the ball clears the wall. m (c) Find the horizontal distance (in m) from the wall to the point on the roof where the ball lands. m (d) What If? If the teacher always launches the ball with the speed found in part (a), what is the minimum angle (in degrees above the horizontal) at which he can launch the ball and still clear the playground railing? (Hint: You may need to use the trigonometric identity sec (0) = 1 + tan (@).) . above the horizontal (e) What would be the horizontal distance (in m) from the wall to the point on the roof where the ball lands in this case? m Need Help? Read It