EBK ESSENTIAL UNIVERSITY PHYSICS, VOLUM
4th Edition
ISBN: 9780135272947
Author: Wolfson
Publisher: VST
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Chapter 2, Problem 85P
Ice skaters, ballet dancers, and basketball players executing vertical leaps often give the illusion of “hanging” almost motionless near the top of the leap. To see why this is, consider a leap to maximum height h. Of the total time spent in the air, what fraction is spent in the upper half (i.e., at
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In the vertical jump, an Kobe Bryant starts from a crouch and jumps upward to reach as high as possible. Even the best athletes spend little more than 1.00 ss in the air (their "hang time"). Treat Kobe as a particle and let ymaxymax be his maximum height above the floor. Note: this isn't the entire story since Kobe can twist and curl up in the air, but then we can no longer treat him as a particle.
Hint: Find v0 to reach y_max in terms of g and y_max and recall the velocity at y_max is zero. Then find v1 to reach y_max/2 with the same kinematic equation. The time to reach y_max is obtained from v0=g (t), and the time to reach y_max/2 is given by v1-v0= -g(t1). Now, t1 is the time to reach y_max/2, and the quantity t-t1 is the time to go from y_max/2 to y_max. You want the ratio of (t-t1)/t1
To explain why he seems to hang in the air, calculate the ratio of the time he is above ymax/2ymax/2 moving up to the time it takes him to go from the floor to that height. You may ignore…
A ball is thrown straight up with an initial velocity of 40 m/s, so that its height (in meters) after t seconds is:
h(t)=2t(20-t)
I don't have answer pages at the end, so ill need an explanation as well, please. Thanks
Kindly do not round off
Chapter 2 Solutions
EBK ESSENTIAL UNIVERSITY PHYSICS, VOLUM
Ch. 2.1 - We just described three trips from Houston to Des...Ch. 2.2 - The figures show position-versus-time graphs for...Ch. 2.3 - An elevator is going up at constant speed, slows...Ch. 2.5 - Standing on a roof, you simultaneously throw one...Ch. 2.6 - The graph shows acceleration versus time for three...Ch. 2 - Under what conditions are average and...Ch. 2 - Does a speedometer measure speed or velocity?Ch. 2 - You check your odometer at the beginning of a days...Ch. 2 - Consider two possible definitions of average...Ch. 2 - Is it possible to be at position x = 0 and still...
Ch. 2 - Is it possible to have zero velocity and still be...Ch. 2 - If you know the initial velocity v0 and the...Ch. 2 - In which of the velocity-versus-time graphs shown...Ch. 2 - If you travel in a straight line at 50 km/h for 1...Ch. 2 - If you travel in a straight line at 50 km/h for 50...Ch. 2 - In 2009, Usain Bolt of Jamaica set a world record...Ch. 2 - Earth’s diameter is approximately 8000 miles....Ch. 2 - Starting front home, you bicycle 24 km north in...Ch. 2 - The Voyager 1 spacecraft is expected to continue...Ch. 2 - Prob. 15ECh. 2 - Whats the conversion factor from meters per second...Ch. 2 - On a single graph, plot distance versus time for...Ch. 2 - For the motion plotted in Fig. 2.15, estimate (a)...Ch. 2 - A model rocket is launched straight upward. Its...Ch. 2 - You’re driving at the 50 km/h speed limit when you...Ch. 2 - Starting from rest, a subway train first...Ch. 2 - Prob. 22ECh. 2 - An egg drops from a second-story window, taking...Ch. 2 - An airplanes takeoff speed is 320 km/h. If its...Ch. 2 - ThrustSSC, the worlds first supersonic car,...Ch. 2 - Youre driving at 70 km/h when you apply constant...Ch. 2 - Prob. 27ECh. 2 - Prob. 28ECh. 2 - Prob. 29ECh. 2 - Starting from rest, a car accelerates at a...Ch. 2 - A car moving initially at 50 mi/h begins slowing...Ch. 2 - In a medical X-ray tube, electrons are accelerated...Ch. 2 - Californias Bay Area Rapid Transit System (BART)...Ch. 2 - Youre driving at speed v0 when you spot a...Ch. 2 - Prob. 35ECh. 2 - Your friend is sitting 6.5 m above you on a tree...Ch. 2 - A model rocket leaves the ground, heading straight...Ch. 2 - A foul ball leaves the bat going straight up at 23...Ch. 2 - A Frisbee is lodged in a tree 6.5 m above the...Ch. 2 - Space pirates kidnap an earthling and hold him on...Ch. 2 - Example 2.3: A jetliner touches down at 288 km/h....Ch. 2 - Prob. 42ECh. 2 - Prob. 43ECh. 2 - Prob. 44ECh. 2 - Example 2.5: A diver drops from a 9.21-m high...Ch. 2 - Prob. 46ECh. 2 - Prob. 47ECh. 2 - Prob. 48ECh. 2 - You allow 40 min to drive 25 mi to the airport,...Ch. 2 - Prob. 50PCh. 2 - You can run 9.0 m/s, 20% faster than your brother....Ch. 2 - Prob. 52PCh. 2 - An objects position is given by x = bt + ct3 where...Ch. 2 - An objects position as a function of time t is...Ch. 2 - In a 400-m drag race, two cars start at the same...Ch. 2 - Squaring Equation 2.7 gives an expression for v2....Ch. 2 - During the complicated sequence that landed the...Ch. 2 - The position of a car in a drag race is measured...Ch. 2 - A fireworks rocket explodes at a height of 82.0 m,...Ch. 2 - The muscles in a grasshoppers legs can propel the...Ch. 2 - On packed snow, computerized antilock brakes can...Ch. 2 - A particle leaves its initial position x0 at time...Ch. 2 - A hockey puck moving at 32 m/s slams through a...Ch. 2 - Prob. 64PCh. 2 - A jetliner touches down at 220 km/h and comes to a...Ch. 2 - A motorist suddenly notices a stalled car and...Ch. 2 - A racing car undergoing constant acceleration...Ch. 2 - The maximum braking acceleration of a car on a dry...Ch. 2 - After 35 min of running, at the 9-km point in a...Ch. 2 - Youre speeding at 85 km/h when you notice that...Ch. 2 - Airbags cushioned the Mars rover Spirits landing,...Ch. 2 - Calculate the speed with which cesium atoms must...Ch. 2 - A falling object travels one-fourth of its total...Ch. 2 - Youre on a NASA team engineering a probe to land...Ch. 2 - Youre atop a building of height h, and a friend is...Ch. 2 - A castles defenders throw rocks down on their...Ch. 2 - Two divers jump from a 3.00-m platform. One jumps...Ch. 2 - A balloon is rising at 10 m/s when its passenger...Ch. 2 - In 2014 the Philae spacecraft became the first...Ch. 2 - Youre at mission control for a rocket launch,...Ch. 2 - Youre an investigator for the National...Ch. 2 - Prob. 82PCh. 2 - Consider an object traversing a distance L, part...Ch. 2 - Prob. 84PCh. 2 - Ice skaters, ballet dancers, and basketball...Ch. 2 - Youre staring idly out your dorm window when you...Ch. 2 - A police radars effective range is 1.0 km, and...Ch. 2 - An object starts moving in a straight line from...Ch. 2 - Youre a consultant on a movie set, and the...Ch. 2 - (a) For the ball in Example 2.6, find its velocity...Ch. 2 - Your roommate is an aspiring novelist and asks...Ch. 2 - Prob. 92PCh. 2 - Derive Equation 2.10 by integrating Equation 2.7...Ch. 2 - An objects acceleration increases quadratically...Ch. 2 - An object’s velocity as a function of time is...Ch. 2 - An objects acceleration decreases exponentially...Ch. 2 - A ball is dropped from rest at a height li0 above...Ch. 2 - A wildlife biologist is studying the hunting...Ch. 2 - A wildlife biologist is studying the hunting...Ch. 2 - A wildlife biologist is studying the hunting...Ch. 2 - A wildlife biologist is studying the hunting...Ch. 2 - A wildlife biologist is studying the hunting...
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