University Physics (14th Edition)
14th Edition
ISBN: 9780133969290
Author: Hugh D. Young, Roger A. Freedman
Publisher: PEARSON
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Chapter 7, Problem 7.84PP
BIO THE DNA SPRING. A DNA molecule, with its double-helix structure, can in some situations behave like a spring. Measuring the force required to stretch single DNA molecules under various conditions can provide information about the biophysical properties of DNA. A technique for measuring the stretching force makes use of a very small cantilever, which consists of a beam that is supported at one end and is free to move at the other end. like a tiny diving board. The cantilever is constructed so that it obeys Hooke’s law—that is the displacement of its free end is proportional to the force applied to it. Because different cantilevers have different force constants, the cantilever's response must first be calibrated by applying a known force and determining the resulting deflection of the cantilever. Then one end of a DNA molecule is attached to the free end of the cantilever, and the other end of the DNA molecule is attached to a small stage that can be moved away from the cantilever, stretching the DNA. The stretched DNA pulls on the cantilever, deflecting the end of the cantilever very slightly. The measured deflection is then used to determine the force on the DNA molecule.
7.84 The stage moves at a constant speed while stretching the DNA. Which of the graphs in Fig. P7.84 best represents the power supplied to the stage versus time?
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Chapter 7 Solutions
University Physics (14th Edition)
Ch. 7 - A baseball is thrown straight up with initial...Ch. 7 - A projectile has the same initial kinetic energy...Ch. 7 - An object is released from rest at the top of a...Ch. 7 - An egg is released from rest from the roof of a...Ch. 7 - A physics teacher had a howling hall suspended...Ch. 7 - Is it possible for a friction force to increase...Ch. 7 - A woman bounces on a trampoline, going a little...Ch. 7 - Q7.8 Fractured Physics. People often call their...Ch. 7 - (a) A book is lifted upward a vertical distance of...Ch. 7 - (a) A block of wood is pushed against a spring,...
Ch. 7 - A 1.0-kg stone and a 10.0-kg stone are released...Ch. 7 - Two objects with different masses are launched...Ch. 7 - When people are cold, they often rub their hands...Ch. 7 - A box slides down a ramp and work is done on the...Ch. 7 - In physical terms, explain why friction is a...Ch. 7 - Since only changes in potential energy are...Ch. 7 - Figure 7.22a shows the potential-energy function...Ch. 7 - Figure 7.22b shows the potential-energy function...Ch. 7 - For a system of two particles we often let the...Ch. 7 - Explain why the points x = A and x = A in Fig....Ch. 7 - A particle is in neutral equilibrium if the net...Ch. 7 - The net force on a particle of mass m has the...Ch. 7 - The potential-energy function for a force F is...Ch. 7 - In one day, a 75-kg mountain climber ascends from...Ch. 7 - BIO How High Can We Jump? The maximum height a...Ch. 7 - CP A 90.0-kg mail bag hangs by a vertical rope 3.5...Ch. 7 - BIO Food Calories. The food calorie, equal to 4186...Ch. 7 - A baseball is thrown from the roof of a...Ch. 7 - A crate of mass M starts from rest at the top of a...Ch. 7 - BIO Human Energy vs. Insect Energy. For its size,...Ch. 7 - Prob. 7.8ECh. 7 - Prob. 7.9ECh. 7 - A 25.0-kg child plays on a swing having support...Ch. 7 - You are testing a new amusement park roller...Ch. 7 - Tarzan and Jane. Tarzan, in one tree, sights Jane...Ch. 7 - CP A 10.0-kg microwave oven is pushed 6.00 m up...Ch. 7 - An ideal spring of negligible mass is 12.00 cm...Ch. 7 - A force of 520 N keeps a certain spring stretched...Ch. 7 - BIO Tendons. Tendons are strong elastic fibers...Ch. 7 - A spring stores potential energy U0 when it is...Ch. 7 - A slingshot will shoot a 10-g pebble 22.0 m...Ch. 7 - A spring of negligible mass has force constant k =...Ch. 7 - A 1.20-kg piece of cheese is placed on a vertical...Ch. 7 - A spring of negligible mass has force constant k =...Ch. 7 - (a) For the elevator of Example 7.9 (Section 7.2),...Ch. 7 - A 2.50-kg mass is pushed against a horizontal...Ch. 7 - A 2.50-kg block on a horizontal floor is attached...Ch. 7 - You are asked to design a spring that will give a...Ch. 7 - A 75-kg roofer climbs a vertical 7.0-m ladder to...Ch. 7 - A 0.60-kg book slides on a horizontal table. The...Ch. 7 - CALC In an experiment, one of the forces exerted...Ch. 7 - A 62.0-kg skier is moving at 6.50 m/s on a...Ch. 7 - Prob. 7.30ECh. 7 - CALC A force parallel to the .v-axis acts on a...Ch. 7 - CALC The potential energy of a pair of hydrogen...Ch. 7 - CALC A small block with mass 0.0400 kg is moving...Ch. 7 - CALC An object moving in the xy-plane is acted on...Ch. 7 - CALC The potential energy of two atoms in a...Ch. 7 - A marble moves along the x-axis. The...Ch. 7 - At a construction site, a 65.0-kg bucket of...Ch. 7 - Two blocks with different masses are attached to...Ch. 7 - A block with mass 0.50 kg is forced against a...Ch. 7 - A 2.00-kg block is pushed against a spring with...Ch. 7 - A 2.00-kg block is pushed against a spring with...Ch. 7 - CP Riding a Loop-the- Loop. A car in an amusement...Ch. 7 - A 2.0-kg piece of wood slides on a curved surface...Ch. 7 - Up and Down the Hill. A 28-kg rock approaches the...Ch. 7 - A 15.0-kg stone slides down a snow-covered hill...Ch. 7 - CP A 2.8-kg block slides over the smooth, icy hill...Ch. 7 - Bungee Jump. A bungee cord is 30.0 m long and,...Ch. 7 - You are designing a delivery ramp for crates...Ch. 7 - The Great Sandini is a 60-kg circus performer who...Ch. 7 - A 1500-kg rocket is to be launched with an initial...Ch. 7 - A system of two paint buckets connected by a...Ch. 7 - These results are from a computer simulation for a...Ch. 7 - CP A 0.300-kg potato is tied to a string with...Ch. 7 - A 60.0-kg skier starts from rest at the top of a...Ch. 7 - Prob. 7.55PCh. 7 - A ball is thrown upward with an initial velocity...Ch. 7 - Prob. 7.57PCh. 7 - A truck with mass m has a brake failure while...Ch. 7 - CALC A certain spring found not to obey Hookes law...Ch. 7 - CP A sled with rider having a combined mass of 125...Ch. 7 - CALC A conservative force F is in the +x-direction...Ch. 7 - A 3.00-kg block is connected to two ideal...Ch. 7 - A 0.150-kg block of ice is placed against a...Ch. 7 - If a fish is attached to a vertical spring and...Ch. 7 - CALC You are an industrial engineer with a...Ch. 7 - A basket of negligible weight hangs from a...Ch. 7 - CALC A 3.00-kg fish is attached to the lower end...Ch. 7 - You are designing an amusement park ride. A cart...Ch. 7 - A 0.500-kg block, attached to a spring with length...Ch. 7 - CP A small block with mass 0.0400 kg slides in a...Ch. 7 - CP A small block with mass 0.0500 kg slides in a...Ch. 7 - CP Pendulum. A small rock with mass 0.12 kg is...Ch. 7 - A wooden block with mass 1.50 kg is placed against...Ch. 7 - CALC A small object with mass m = 0.0900 kg moves...Ch. 7 - CALC A cutting tool under microprocessor control...Ch. 7 - A particle moves along the x-axis while acted on...Ch. 7 - Prob. 7.77PCh. 7 - DATA A long ramp made of cast iron is sloped at a...Ch. 7 - DATA A single conservative force F(x) acts on a...Ch. 7 - CALC A proton with mass m moves in one dimension....Ch. 7 - BIO THE DNA SPRING. A DNA molecule, with its...Ch. 7 - BIO THE DNA SPRING. A DNA molecule, with its...Ch. 7 - BIO THE DNA SPRING. A DNA molecule, with its...Ch. 7 - BIO THE DNA SPRING. A DNA molecule, with its...
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