Can you solve for the answers and show the work for each, except for the multiple choices

1. An object is dropped from rest and falls freely 20. meters to Earth. When is the speed of the object 9.8 meters per second? A) during the entire first second of its fall B) at the end of its first second of fall C) during its entire time of fall D) after it has fallen 9.8 meters 2. You drop a stone down off a bridge. You are able to count to 4.0 seconds when it finally hits the water. How high is the bridge? 3. Niagara Falls is 51 meters high. If you dropped a ball off the ledge, how much time would it take it to hit the water? 4. If you dropped your cell phone from a height of 1.20 m above the ground, with what speed would it strike the ground? 5. An astronaut drops a rock on planet X from a height of 0.72 m above the ground. If it takes 0.63 seconds for the rock to strike the ground, what is the acceleration on planet X? 6. Which graph best represents the motion of a freely falling body near the Earth's surface? A) B) D) SPEED SPEED SPEED SPEED TIME TIME TIME TIME 7. An 8.0 kg bowling ball is dropped from a height of 20.0 meters above the ground. Which graph below best represents the relationship between acceleration (a) and time (t) for the object? A) B) D) 8. A ball is thrown vertically upward with an initial velocity of 29.4 meters per second. What is the maximum height reached by the ball? 9. You fire a paintball from a paintball gun straight up into the air at 25.0 m/s. a. What is the instantaneous velocity at the top of its flight? (no calculation required) b. What is the acceleration at the top of its flight? (no calculation required) . What is the maximum height the paintball will reach? 10. A Nerf gun is shot straight up from the ground with an initial velocity of 14.0 m/s. What is the total time the projectil is in the air? Selected Answers 2. 78.4 m 3. 3.23 s 4. 4.85 m/s 5. 3.6 m/s2 8. 44.1 m 9. c) 31.9 m 10. 2.86 s