Free fall example A watermelon is dropped from the edge of the roof of a building and falls to the ground. You noticed that it takes 2.5 s for the watermelon to reach the ground. What is the height of the building? How fast does the watermelon move just before it hits the ground? How fast does the watermelon move as it passes through the midpoint of its journey?

Free fall example A watermelon is dropped from the edge of the roof of a building and falls to the ground. You noticed that it takes 2.5 s for the watermelon to reach the ground. What is the height of the building? How fast does the watermelon move just before it hits the ground? How fast does the watermelon move as it passes through the midpoint of its journey?

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter3: Motion In Two Dimensions

Section: Chapter Questions

Problem 11P

See similar textbooks

Similar questions

Two cars are moving in the same direction in parallel lanes along a highway. At some instant, the velocity of car A exceeds the velocity of car B. Does that mean that the acceleration of A is greater than that of B at that instant? Explain.
A bicycle racer sprints at the end of a race to clinch a victory. The racer has an initial velocity of 11.5 m/s and accelerates at the rate of 0.500 m/s2 for 7.00 s. (a) What is his final velocity? (b) The racer continues at this velocity to the finish line. If he was 300 m from the finish line when he started to accelerate, how much time did he save? (c) One other racer was 5.00 m ahead when the winner started to accelerate, but he was unable to accelerate, and traveled at 11.8 m/s until the finish line. How far ahead of him (in meters and in seconds) did the winner finish?
A rescue helicopter is hovering over a person whose boat has sunk. One of the rescuers throws a life preserver straight down to the victim with an initial velocity of 1.40 m/s and observes that it takes 1.8 s to reach the water. (a) List the knowns in this problem. (b) How high above the water was the preserver released? Note that the downdraft of the helicopter reduces the effects of air resistance on the falling life preserver, so that an acceleration equal to that of gravity is reasonable.
Bryan Allen pedaled a human-powered aircraft across the English Channel from the cliffs of Dover to Cap Gris-Nez on June 12, 1979. (a) He flew for 169 min at an average velocity of 3.53 m/s in a direction 45° south of east. What was his total displacement? (b) Allen encountered a headwind averaging 2.00 m/s almost precisely in the opposite direction of his motion relative to the Earth. What was his average velocity relative to the air? (c) What was his total displacement relative to the air mass?
A speedboat travels in a straight line and increases in speed uniformly from i = 20.0 m/s to f = 30.0 m/s in displacement x of 200 m. We wish to find the time interval required for the boat to move through this displacement, (a) Draw a coordinate system for this situation, (b) What analysis model is most appropriate for describing this situation? (c) From the analysis model, what equation is most appropriate for finding the acceleration of the speedboat? (d) Solve the equation selected in part (c) symbolically for the boats acceleration in terms of i, f, and x. (e) Substitute numerical values lo obtain the acceleration numerically. (f) Find the time interval mentioned above.
An express train passes through a station. It enters with an initial velocity of 22.0 m/s and decelerates at a rate of 0.150 m/s2 as it goes through. The station is 210 m long. (a) How long is the nose of the train in the station? (b) How fast is it going when the nose leaves the station? (c) If the train is 130 m long, when does the end of the train leave the station? (d) What is the velocity of the end of the train as it leaves?
Figure P4.8 shows the motion diagram of two balls, one on the left and one on the right. Each ball starts at a point labeled i. The ball on the left is released and falls straight down. At the same time, the ball on the right is launched horizontally and follows the path shown. a. Use the given coordinate system to write the position of points i, C, E, G, and K in component form for each ball. b. Find the displacement of each ball from i to points C, E, G, and K. c. Compare your answers for the two balls in part (b). What similarities do you notice? FIGURE P4.8 Problems 8 and 26.
A motorist drives for 35.0 minutes at 85.0 km/h and then stops for 15.0 minutes. He then continues north, traveling 130. Km in 2.00 h. (a) What is his total displacement? (b) What is his average velocity?
Case Study Crall and Whipple attached a fan to a cart placed on a level track and then released the cart. They made a position-versus-time graph (Fig. P2.54) and fit a curve to these data such that x=0.036m+(0.0080m/s)t+(0.10m/s2)t2 a. Find and graph the velocity as a function of time. b. What is the shape of the velocity-versus-time graph? What do you expect the acceleration-versus-time graph to look like? Explain. c. Find and graph the acceleration as a function of time.
A swimmer bounces straight up from a diving board and falls feet first into a pool. She starts with a velocity of 4.00 m/s, and her takeoff point is 1.80 m above the pool. (a) How long are her feet in the air? (b) What is her highest point above the board? (c) What is her velocity when her feet hit the water?
(a) A jet airplane flying from Darwin, Australia, has an air speed of 260 m/s in a direction 5.0° south of west. It is in the jet stream, which is blowing at 35.0 m/s in a direction 15° south of east. What is the velocity of the airplane relative to the Earth? (b) Discuss whether your answers are consistent with your expectations for the effect of the wind on the plane's path.
An athlete leaves one end of a pool of length L at t = 0 and arrives at the other end at time t1. She swims back and arrives at the starting position at time t2. If she is swimming initially in the positive x direction, determine her average velocities symbolically in (a) the first half of the swim, (b) the second half of the swim, and (c) the round trip. (d) What is her average speed for the round trip?