14. A rock is thrown downwards with an initial velocity of 8.0 mfs. What is the velocity of the rock after 1.5 s? 15. The direction of acceleration is determined by the change in velocity (Av = Vf v0). Complete the following table, then below the table invent a situation where these velocities might happen. \"A\" is done for you. a [pas or neg) A. A person. at a stopL'Lgl/itpmsses the gas aw! goes from still (0W5) to loud/S 16. Explain why the following misconceptions are false. a) If acceleration is zero, the object must be standing still. b) Velocity and acceleration are always the same sign (both positive or both negative). c) If speed is increasing, acceleration must be positive. 10. 11. 12. 13. A toboggan accelerates from rest at 1.1 misE. After 10. seconds, how fast is it going? Show the equation used and all steps. At the bottom of the hill, the toboggan moving 12 mfs forward accelerates at -0.50 mls2 for 10 5. What is the toboggan's velocity at the end of the 10 5? Show the equation used and all steps. How much time does it take a car travelling south at 12 ms to increase its velocity to 26mls south if it accelerates at 3.5 mls2 south? Show the equation used and all steps. The acceleration of a freely falling object (near Earth), when we assume no air resistance, is {remember units). The assumption of no air resistance is never totally true but is often close enough to make pretty accurate calculations. Discuss the properties of free-falling masses where this is a really good assumption and when it isn't. An apple falls from a tree heading directly for Newton's head. What is its velocity after 1 second? After 2 seconds? A ball is thrown straight up into the air at 14 mils. How long does it take for the ball to slow down to an upward velocity of6.0 mis? Show the equation used and all steps. If you throw a rock up into the air, when is its velocity zero? What is the acceleration when the velocity is zero? 1. The pool ball shown below was photographed 8 times at equal time intervals. Is the pool ball's motion uniform? How do you know? Sketch a d vs t and v vs t graph, showing the general shape of each graph. 2. Make a sketch of what the pool ball's photos would look like if it were accelerating (both positively and negatively). 3. Acceleration is often a difficult term to understand. How could you best explain the acceleration of a car (and how it's different then velocity) to a non-physicist? 4. How can you recognize uniform motion on a d vs t graph? 5. What are common units for the following: a. Displacement / Distance (provide 6 examples and circle the SI standard one): b. Time (provide 3 and circle the SI standard one): c. Velocity / Speed (provide 4 and circle the SI standard one): d. Acceleration (provide 3 and circle the SI standard one)