Conceptual Questions
1. A person gets in an elevator on the ground floor and rides it to the top floor of a building. Sketch a velocity-versus-time graph for this motion.
2.
a. Give an example of a vertical motion with a positive velocity and a negative acceleration.
b. Give an example of a vertical motion with a negative velocity and a negative acceleration.
5. You are driving down the road at a constant speed. Another car going a bit faster catches up with you and passes you. Draw a position graph for both vehicles on the same set of axes and note the point on the graph where the other vehicle passes you.
8. A ball is thrown straight up into the air. At each of the following instants, is the ball's acceleration ay equal to g, -g, 0, g?
a. Just after leaving your hand.
b. At the very top (max height).
c. Just before hitting the ground.
9. A ball is thrown straight up in the air. Answer the following questions based on the following positions of the ball. A-when it leaves the person's hand. B-halfway to its maximum height.C-at its maximum height. D- ¼ of the way down. E- Just before it hits the ground.
a. Rank the acceleration of the ball at each position from greatest to least.
b. Rank the velocities of the ball at each position from greatest to least.
10. The figure below shows an object's position vs time graph. The letters A to E correspond to various segments of the motion in which the graph has a constant slope.
a. Write a realistic motion short story for an object that would have this position graph (be creative J)
b. In which segment(s) is the object at rest?
c. In which segment(s) is the object moving to the right?
d. Is the speed of the object during segment C greater than, equal to, or less than its speed during segment E? Explain.
25. A car can go from 0 to 60 mph in 7.0 s. Assuming that it could maintain the same acceleration at higher speeds, how long would it take the car to go from 0 to 120 mph?
2.2 Uniform Motion
7. In major league baseball, the pitcher's mound is 60 ft from the batter. If a pitcher throws a 95 mph fastball, how much time elapses from when the ball leaves the pitcher's hand until the ball reaches the batter?
10. Richard is driving home to visit his parents. 125 mi of the trip are on the interstate highway where the speed limit is 65 mph. Normally Richard drives at the speed limit but today he is running late and decides to take his chances by driving at 70 mph. How many minutes does he save?
12. In an 8.00 km race, one runner runs at a steady 11.0 km/hr and another runs at 14.0 km/hr. How far from the finish line is the slower runner when the faster runner finishes the race?
26. When striking, the pike, a predatory fish can accelerate from rest to a speed of 4.0 m/s in 0.11 s.
a. What is the acceleration of the pike during this strike?
b. How far does the pike move during this strike?
28. When jumping, a flea rapidly extends its legs, reaching a takeoff speed of 1.0 m/s over a distance of 0.50 mm.
a. What is the flea's acceleration as it extends its legs?
b. How long does it take the flea to leave the ground after it begins pushing off?
29. A car traveling at speed v takes distance d to stop after the breaks are applied. What is the stopping distance if the car is initially traveling at speed 2v? Assume that the acceleration due to the braking is the same in both cases.
31. A cross-country skier is skiing along at a zippy 8.0 m/s. She stops pushing and simply glides along, slowing to a reduced speed of 6.0 m/s after gliding for 5.0 m. What is the magnitude of her acceleration as she slows?