Name: Physical Science Packet 5.3 Net Force: Fnet=ma Test and Packet Due on Fri 2/20! Tutoring: Wed-Fri 3:20-4:20 Period: Questions? Text or Email Mr. Barnhart 901-654-7797 [email protected] barnhartmelrose.weebly.com Learning Targets Monday: I can . Tuesday: I can . Wednesday: I can . Thursday: I can . Friday: I can dominate the quiz. A1. Write the symbol AND name of the quantity described a. how fast an object is moving b. how much an object’s speed changes each second c. how long (seconds) an object was moving d. how far an object moved e. how much “stuff” (protons, neutrons, electrons) an object is made of f. extra force in a direction g. pull by a rope, cable…etc h. resistive force due to moving through air i. force due to contact with a hand, ground … etc j. active push off surface (along the surface) k. active push off the air l. gravitational pull of the earth s speed m. resistive force due to moving across a surface n. measurement of the roughness of surfaces (difficulty for sliding) o. measurement of ability to catch air (area & shape) p. describes the direction an object is moving A2. What synonym do we use for “net” in our definition of net force? A3. If all the forces on an object are balanced, what can the object be doing? What law of physics is this? A4. Explain how to determine whether an object’s speed will increase or decrease based on the net force and velocity. A5. What equation relates forces to motion? What law of physics is this? A6. A fan and masses are placed on a cart on a flat track. Describe two ways to increase the fan-cart’s acceleration. Which one of Newton’s Laws does this exemplify? Bellwork Answers. Always explain why!!! bellwork.1 bellwork.2 bellwork.3 Exit Ticket Answers. Always explain why!!! exit.ticket.1 exit.ticket.2 exit.ticket.3 B. Spiraled Skills i. equation [assume uniform accelerations] B1. B2. B3. B4. lFnetl = 600N lFnetl = ? W =? W = 600N m = 80kg m = 12kg m = 50kg m = ? a =? a = 3m/s2 ____ correct B5. ____ correct ____ correct B6. N = 60N B7. B8. N = 500N bf = ? D =? bf = ? μ = 0.4 ____ correct B9. si = ? k = μ = 0.05 s ____ correct D = 470N 20N/m/s = 25m/s k = 20N/m/s a = 30ft/s2 = 1.85s =? ____ correct B11. ṡ =? d = 90m d = 300m t = ? t = 3.25s ____ correct s ____ correct B10. sf = 0 t ____ correct a = 10m/s2 ____ correct ____ correct ii. time –speed charts B12. A student fires a cannonball vertically upwards with a speed of 30m/s. What is the cannonball’s total flight time? The free-fall acceleration is 10m/s2 B13. A student drops a baseball off the top of a building. If the ball strikes the ground 4s later, what was the ball’s final speed? The free-fall acceleration is 10m/s s =0 B14. Make a time-speed chart for a bicyclist, initially traveling 24mph who slows to a stop in 6s. STOP si = si = sf = a= si = t sf = a= t What is the cannonball’s total flight time? s sf = a= s t What is the cannonball’s speed after 4s? What is the initial speed of the ball? s What is the final speed of How long (in seconds) the ball does it take for the bicyclist to stop? What is bicyclists speed after 3s? C. Free-Body Diagrams C1. Bicyclist (pedaling) C2. Bicyclist (coasting) ____ correct C4. Physics Book ____ correct C5. Projectile (neglect Drag) The Seven Force Questions: W: Is the object affected by gravity? N: Is the object touching a surface? T: Is a rope/string pulling the object? D: Is the object moving? bf: Is the object moving on a surface? ff: Is a bike pedaling/car pressing gas? Th: Is a rocket burning fuel/helicopter blades spinning/fan on? Force Directions W: down, N: opposite surface, T: from object along string, D: opposite motion, bf: opposite motion, ff: forward, Th: opposite air push ____ correct C6. Skateboarder (neglect bf, D) PHYSICS FOR WOLVES Replinger & Barnhart ____ correct C7. Load on the ground. ____ correct C8. Hanging load. ____ correct C9. Box (neglect bf, D) load counter weight counter weight load counter weight counter weight chassis chassis ____ correct C10. Fan-Cart (the fan is on, neglect bf, D) ____ correct ____ correct C11. Fan-Cart (the fan is on, neglect bf, D) ____ correct ____ correct C12. Fan (on, blowing air upwards) ____ correct D. Free-Body Diagram Analysis D1. velocity direction: Fnet = speed is D2. velocity direction: Fnet = speed is 7N D3. velocity direction: Fnet = speed is 7N 7N 3N 2N 4N 2N 7N 7N 7N ____ correct D4. velocity direction: Fnet = speed is ____ correct D5. velocity direction: Fnet = speed is 3,000lb 120lb ____ correct D6. velocity direction: Fnet = speed is ? 120lb 200lb 50lb ? 120lb 170lb 50lb 3,000lb 3,000lb velocity direction: Fnet = speed is 3,000lb ____ correct D8. velocity direction: Fnet = speed is ____ correct D9. velocity direction: Fnet = speed is 200lb 90lb 160lb 150lb 50lb ____ correct D7. 3N 160lb 160lb ____ correct ____ correct ____ correct D10. velocity direction: Fnet = speed is D11. velocity direction: Fnet = speed is 130N D12. velocity direction: Fnet = speed is 85N U S A U S A U S A 40N 40N 60N 40N 60N 60N ____ correct D13. velocity direction: Fnet = speed is ____ correct D14. velocity direction: Fnet = speed is ____ correct D15. velocity direction: Fnet = speed is 5N U S A ? 70N 0.4N 200N 40N 500N 60N 5N ____ correct D16. velocity direction: Fnet = speed is ____ correct D17. velocity direction: Fnet = speed is ? D18. velocity direction: Fnet = speed is ? 110N 70N ____ correct 80N 70N 40N ? 70N 40N 500N 60N 500N ____ correct 500N ____ correct ____ correct

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