EP PHYSICS: PRIN.APP.AP-MOD.MASTERING
7th Edition
ISBN: 9780137453276
Author: GIANCOLI
Publisher: SAVVAS L
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Textbook Question
Chapter 4, Problem 8Q
(a) Why do you push down harder on the pedals of a bicycle when first starting out than when moving at constant speed? (b) Why do you need to pedal at all when cycling at constant speed?
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A car starts rolling down a 1-in-4 hill (1-in-4 means that for each 4 m traveled along the sloping road, the elevation change is 1 m). How fast is it going when it reaches the bottom after traveling 55 m? (a) Ignore friction. (b) Assume an effective coefficient of friction equal to 0.10.
A person drags a sled across a frozen lake to town. The surface of the lake is quite smooth and slippery (so the friction from the ice can be neglected), but he has studded boots with nails driven through the soles (from the inside) so he can walk across the ice without slipping.
Once the sled is moving at a reasonable speed (about the pace he can walk comfortably), in order to keep the sled moving at this speed he needs to
Pull with a constant force.
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(a) Why do you push down harder on the pedals of a bicycle when first starting out than when moving at constant speed? (b) Why do you need to pedal at all when cycling at constant speed?
Chapter 4 Solutions
EP PHYSICS: PRIN.APP.AP-MOD.MASTERING
Ch. 4 - A 150-kg football player collides head-on with a...Ch. 4 - A line by the poet T. S. Eliot (from Murder in the...Ch. 4 - Why does a child in a wagon seem to fall backward...Ch. 4 - A box rests on the (frictionless) bed of a truck....Ch. 4 - Prob. 3QCh. 4 - If the acceleration of an object is zero, are no...Ch. 4 - Prob. 5QCh. 4 - Prob. 6QCh. 4 - Prob. 7QCh. 4 - (a) Why do you push down harder on the pedals of a...
Ch. 4 - A stone hangs by a fine thread from the ceiling,...Ch. 4 - Prob. 10QCh. 4 - Prob. 11QCh. 4 - Prob. 12QCh. 4 - Prob. 13QCh. 4 - Prob. 14QCh. 4 - Prob. 15QCh. 4 - Prob. 16QCh. 4 - Prob. 17QCh. 4 - Prob. 18QCh. 4 - Prob. 19QCh. 4 - A block is given a brief push so that it slides up...Ch. 4 - Prob. 21QCh. 4 - Prob. 22QCh. 4 - A truck is traveling horizontally to the right...Ch. 4 - You are trying to push your stalled car. Although...Ch. 4 - Matt, in the foreground of Fig. 4-39, is able to...Ch. 4 - A bear sling, Fig. 4-40, is used in some national...Ch. 4 - What causes the boat in Fig. 4-41 to move forward?...Ch. 4 - A person stands on a scale in an elevator. His...Ch. 4 - When a skier skis down a hill, the normal force...Ch. 4 - A golf ball is hit with a golf club. While the...Ch. 4 - Suppose an object is accelerated by a force of 100...Ch. 4 - You are pushing a heavy box across a rough floor....Ch. 4 - Prob. 11MCQCh. 4 - The normal force on an extreme skier descending a...Ch. 4 - To pull an old stump out of the ground, you and a...Ch. 4 - What force is needed to accelerate a sled (mass =...Ch. 4 - Prob. 2PCh. 4 - How much tension must a rope withstand if it is...Ch. 4 - According to a simplified model of a mammalian...Ch. 4 - Superman must stop a 120-km/h train in 150 m to...Ch. 4 - A person has a reasonable chance of surviving an...Ch. 4 - What average force is required to stop a 950-kg...Ch. 4 - Prob. 8PCh. 4 - Prob. 9PCh. 4 - Prob. 10PCh. 4 - Prob. 11PCh. 4 - Prob. 12PCh. 4 - Prob. 13PCh. 4 - Prob. 14PCh. 4 - Prob. 15PCh. 4 - Prob. 16PCh. 4 - Prob. 17PCh. 4 - Prob. 18PCh. 4 - Prob. 19PCh. 4 - A box weighing 77.0 N rests on a table. A rope...Ch. 4 - Figure 4-46
Problem 21.
21. (I) Draw the free-body...Ch. 4 - Prob. 22PCh. 4 - Arlene is to walk across a “high wire" strung...Ch. 4 - A window washer pulls herself upward using the...Ch. 4 - One 3.2-kg paint bucket is hanging by a massless...Ch. 4 - Prob. 26PCh. 4 - A train locomotive is pulling two cars of the same...Ch. 4 - Prob. 28PCh. 4 - At the instant a race began, a 65-kg sprinter...Ch. 4 - A 27-kg chandelier hangs from a ceiling on a...Ch. 4 - Prob. 31PCh. 4 - Figure 4-53 [shows a block (mass mA) on a smooth...Ch. 4 - Prob. 33PCh. 4 - Prob. 34PCh. 4 - 35. (Ill) Suppose the pulley in Fig. 4-55 is...Ch. 4 - Prob. 36PCh. 4 - A force of 35.0 N is required to start a 6.0-kg...Ch. 4 - Prob. 38PCh. 4 - Prob. 39PCh. 4 - Prob. 40PCh. 4 - Prob. 41PCh. 4 - A box is given a push so that it slides across the...Ch. 4 - Prob. 43PCh. 4 - Prob. 44PCh. 4 - Prob. 45PCh. 4 - 46. (II) For the system of Fig. 4-32 (Example...Ch. 4 - Prob. 47PCh. 4 - Prob. 48PCh. 4 - Prob. 49PCh. 4 - A person pushes a 14.0-kg lawn mower at constant...Ch. 4 - Prob. 51PCh. 4 - (a) A box sits at rest on a rough 33° inclined...Ch. 4 - Prob. 53PCh. 4 - Prob. 54PCh. 4 - Prob. 55PCh. 4 - A 25.0-kg box is released on a 27° incline and...Ch. 4 - Prob. 57PCh. 4 - Prob. 58PCh. 4 - The crate shown in Fig. 4-60 lies on a plane...Ch. 4 - A crate is given an initial speed of 3.0 m/s up...Ch. 4 - Prob. 61PCh. 4 - Prob. 62PCh. 4 - The coefficient of kinetic friction for a 22-kg...Ch. 4 - On an icy day, you worry about parking your car in...Ch. 4 - Two masses mA= 2.0 kg and mB= 5.0 kg are on...Ch. 4 - Prob. 66PCh. 4 - Prob. 67PCh. 4 - A 2.0-kg purse is dropped from the top of the...Ch. 4 - Prob. 69GPCh. 4 - 70. A 75.0-kg person stands on a scale in an...Ch. 4 - Prob. 71GPCh. 4 - Prob. 72GPCh. 4 - Prob. 73GPCh. 4 - Prob. 74GPCh. 4 - Prob. 75GPCh. 4 - (a) What minimum force F is needed to lift the...Ch. 4 - Prob. 77GPCh. 4 - A jet aircraft is accelerating at 3.8 m/s2 as it...Ch. 4 - Prob. 79GPCh. 4 - Prob. 80GPCh. 4 - Prob. 81GPCh. 4 - Prob. 82GPCh. 4 - Prob. 83GPCh. 4 - Prob. 84GPCh. 4 - Prob. 85GPCh. 4 - Prob. 86GPCh. 4 - Prob. 87GPCh. 4 - Prob. 88GPCh. 4 - Prob. 89GPCh. 4 - Prob. 90GPCh. 4 - A 72-kg water skier is being accelerated by a ski...Ch. 4 - Prob. 92GPCh. 4 - Prob. 93GPCh. 4 - Prob. 94GPCh. 4 - Prob. 95GPCh. 4 - Prob. 96GPCh. 4 - Prob. 97GP
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