Only practice problem 3.6The second photo has background info to help solve the problem Page 76- Practice Problem 3.6If the kicker gives the ball the same initial speed and anglebut the ball is kicked from a point 25m from the goalpost,what is the height of the ball above the crossbar as itcrosses over the goalpost? Answer: 1.2m.Page 77- Practice problem 3.7Suppose the pear is released from a height of 6.00m abovethe archer's arrow, the arrow is shot at a speed of 30.0m/s,and the distance between the archer and the base of thetower is 15.0m. Find the time at which the arrow hits thepear, the distance the pear has fallen, and the height of thearrow above its release point. Answers: 0.54s, 1.4m, 4.6m.Page 80-Practice Problem 3.8A more reasonable maximum acceleration for varyingpavement conditions is 5.0m/s². Under these conditions,what is the maximum speed at which a car can negotiate aflat curve with radius 230m? Answer: 34m/s=76mi/h.Page 81- Practice Problem 3.9If the ride increases in speed so that T = 2.0S, what is a rad?(this question can be answered by using proportionalreasoning, without much arithmetic.) Answer: 49 m/s².Page 83 - Practice Problem 3.10If the plane its airspeed of 240km/h, but the winddecreases, what is the wind speed if the plane's velocitywith respect to earth is 15° east of north? Answer: 64 km/h.Page 84 - Practice Problem 3.11If the pilot was forced to reduce the plane's speed to150km/h, how much would she need to increase the angleat which the plane is pointing (relative to north) in order forthe plane to continue to travel due north? Answer: 8.7° 781 =CHAPTER 3 Motion in a PlaneEXAMPLE 3.6 Kicking a field goalIn this example we will look at the more complex question of whether or not a projectile will clear a certainheight at a specific point in its trajectory. Consider a field goal attempt, where a football is kicked from apoint on the ground that is a horizontal distance d from the goalpost. For the attempt to be successful, thethe kicker's foot with an initial speed of 20.0 m/s at an angle of 30.0° above the horizontal. What is the dis-ball must clear the crossbar, 10 ft (about 3.05 m) above the ground, as shown in Figure 3.16. The ball leavestance d between kicker and goalpost if the ball barely clears the crossbar on its way back down?SOLUTIONSET UP We use our idealized model of projectile motion, in which weassume level ground, ignore the effects of air resistance, and treat thefootball as a point particle. We place the origin of coordinates at thepoint where the ball is kicked. Then xo = = 0,Vax=Uo cos 30.0°= (20.0 m/s) (0.866) = 17.3 m/s, andVoy Do sin 30.0°= (20.0 m/s) (0.500)= 10.0 m/s.SOLVE We first ask when (i.e., at what value of t) the ball is at a heightof 3.05 m above the ground; then we find the value of x at that time.When that value of x is equal to the distance d, the ball is just barelypassing over the crossbar.To find the timewhen y = 3.05 m, we use the equationy = y + Voyt - gr². Substituting numerical values, we obtain3.05 m = (10.0 m/s)t - (4.90 m/s²)².This is a quadratic equation; to solve it, we first write it in standardform: (4.90 m/s²)² (10.0 m/s)t + 3.05 m = 0. Then we use thequadratic formula. (See Chapter 0 if you need to review it.) We get2(4.9 m/s²)x (10.0 m/s= 0.373 s, 1.67 s.± √(10.0 m/s)2 - 4(4.90 m/s²) (3.05 m)There are two roots: t = 0.373 s and t = 1.67 s. The ball passes theheight 3.05 m twice, once on the way up and once on the way down.We need to find the value of x at each of these times, using the equationfor x as a function of time. Because xo = 0, we have simply x = Vod.EXAMPLE 3.7 Shooting a falling3.05 mVo20.0 m/so30.0⁰OX!!A FIGURE 3.16 Kicking a field goal.DVideo Tutor SoluThe ball will have sufficient height to clear the goalpostat two different values of x. However, only the height atx = d describes the ball on its way back down.For t = 0.373 s, we get x = (17.3 m/s) (0.373 s) = 6.45 m, and fort = 1.67 s, we get x = (17.3 m/s) (1.67 s) = 28.9 m. So, if the goal-post is located between 6.45 m and 28.9 m from the initial point, theball will pass over the crossbar; otherwise, it will pass under it.REFLECT The distance of 28.9 m is about 32 yd; field goal attemptsare often successful at that distance. The ball passes the height y = 10 fttwice, once on the way up (when t = 0.373 s) and once on the waydown (when t = 1.67 s). To verify this, we could calculate u, at bothtimes; when we do, we find that it is positive (upward) at t = 0.373 sand negative (downward) with the same magnitude at t = 1.67 s.Practice Problem: If the kicker gives the ball the same initial speedgoalpost? Answer: 1.2 m.and angle but the ball is kicked from a point 25 m from the goalpost,what is the height of the ball above the crossbar as it crosses over theSOLUTIONSET UP Tthere is soy coordinashoots thetal distancwe derivesame. Thetime; if thSOLVE TFor the aXarrow =pear are eNow wewe haveat

Answered: Image /qna-images/answer/3c166b1d-503e-469c-b0ce-a8ed585b1d15.jpg

Answered: Page 76- Practice Problem 3.6 If the…

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter1: Units, Trigonometry. And Vectors

Section: Chapter Questions

Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...