A7. Average Velocity: Round Trip of a Blow Dart. (a) Fire a blow dart straight up into the air and wait for it to come back down to its initial position. Question: for the entire flair what is the average velocity? (A very quick estimate is fine - this question takes you more than I or 2 minutes to answer. then discuss this with a friend or your problem session instructor. (b) Now, fire the blow dart at an angle somewhere in the viciting of 45 (the actual angle isn't critical). Watch the entire flight, zad comment on the average velocity (both magnitude and direction - if not zero). A8. Vector Addition: Walking Around. (a) Using the method of components. add the following rectors. and determine the I-component and y-component of the total and the magnitude and direction of the total: 10 paces at 45 . 12 paces z 90. 17 paces at -45 , and 10 paces at -135. (b) Do the experiment. We will do the following as a class exercise during problem session. so you don't have to do this on your on On a sunny day, pick a starting location in the middle of an opa field or grassy area. (Lamp posts work well.) Choose the direction that your shadow casts as the 0' direction and imagine a 360 around that direction. Now. walk 10 paces at an angle of $5 (ros ] be taking your shadow with you. so you you'll be able to see that put are walking at the correct angle). Then. walk 12 paces at an angie of 90 . 17 paces at an angle of 45 . and 10 paces at - 135 . When do you end up relative to your starting location? Does this aga with your calculation? Write down how you compared your res with your calculation. Page 1 / 2 + W S P 3and th a constant speed. as shown in the figure. How Open with Google Docs 20 seconds of its motion? At( m/ 5) 30 20 10 12 20 24 28 t(s) Figure 12: Figure for Problem A90. A91. Velocities of clock hands A clock has an hour hand of length 2.4 cm and a minute hand of length 3.8 cm. (a) Calculate the position and velocity of the hour hand at noon. (b) Calculate the position and velocity of the minute hand at 12:15. A92. Velocity addition/subtraction for an airplane You are a pilot beginning a 1500-km flight. Your plane's speed is 1000 km/hr, and air traffic control says you'll have to head 15 west of south to maintain a southward course. If the flight takes 100 min. what's the wind velocity? A93. Spring ejector on rotating platform A massless spring with constant & is mounted on a turntable of rotational inertia I, as shown. The turntable is on a frictionless vertical axle, though ini- tally it's not rotating. The spring is com- pressed a distance d from its equilibrium, with a mass m placed against it. When the spring is released, the mass moves at right angles to a line through the turntable's center, at a distance b from the center. and slides without friction across the table and off the edge. Find expressions for (a) the final linear speed of the mass and (b) the final rotational speed of the turntable. Hint: What's conserved? Additional hint: you have to solve par Page 2 7 2 anjoushy + S Ed