Concept explainers
(a)
The expression for the distance
(a)
Explanation of Solution
Introduction:
To derive the expression for distance the box slides, the work-energy theorem will be used. Work-energy theorem states that work done by any external force on a body is equal to the change in total energy of that body.
Write the expression for friction force.
Here,
Write the expression for thermal energy.
Here,
Substitute
Write the expression for change in kinetic energy.
Here,
Write the expression for change in gravitational potential energy.
Here,
Write the expression for change in spring potential energy.
Here,
Write the expression of work done by external force.
Here,
Substitute
Substitute
Conclusion:
Thus, the expression for the distance
(b)
The expression of speed for the box slides the distance
(b)
Explanation of Solution
Introduction:
To derive the expression for distance the box slides, the work-energy theorem will be used. Work-energy theorem states that work done by any external force on a body is equal to the change in total energy of that body.
Write the expression for friction force.
Here,
Write the expression for thermal energy.
Here,
Substitute
Write the expression for change in kinetic energy.
Here,
Write the expression for change in gravitational potential energy.
Here,
Write the expression for change in spring potential energy.
Here,
Write the expression of work done by external force.
Here,
Substitute
Substitute
Conclusion:
Thus, the expression of speed for the box slides the distance
(a)
The value of coefficient of friction for
(a)
Explanation of Solution
Introduction:
To derive the expression for distance the box slides, the work-energy theorem will be used. Work-energy theorem states that work done by any external force on a body is equal to the change in total energy of that body.
Write the expression for friction force.
Here,
Write the expression for thermal energy.
Here,
Substitute
Write the expression for change in kinetic energy.
Here,
Write the expression for change in gravitational potential energy.
Here,
Write the expression for change in spring potential energy.
Here,
Write the expression of work done by external force.
Here,
Substitute
Substitute
Conclusion:
Thus, the value of coefficient of friction for
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Chapter 7 Solutions
Physics for Scientists and Engineers
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- The collar of 5 kg mass shown in the figuremoves on a parabolic bar on a horizontal plane.The collar has a speed of 8 m/sec when it is atpoint B. Determine the friction force betweenthe collar and the bar if the coefficient offriction is 0.25. Formula of the parabolic bar isshown in the figure.arrow_forward(a) A cube of Jell-0 6 cm on a side sits on your plate. You exert a horizontal force of 0.20 N on thetop surface parallel to the surface and observe a sideways displacement of 5 mm. What is the shearmodulus of the Jell-O? (b) A molecule in a microwave oven experiences a torque τ = τ0 sin θ. How much work must bedone to rotate the molecule from θ = 0° to = 180° ?(c) The evolution of a star depends on its size. If a star is sufficiently large, the gravity forcesholding it together may be large enough to collapse it into a very dense object composed mostlyof neutrons. The density of such a neutron star is about 1014 times that of the earth. Suppose thata star initially had a radius about that of our sun, 7 × 108 km, and that it rotated once every 26 days,as our sun does. What would be the period of rotation (the time for 1 rev) if the star collapsed to aradius of 15 km?arrow_forwardThe spring force is initially greater than friction, so the block accelerates forward. But eventually the spring force decreases enough so that it is le (decelerates). In a physics lab experiment, one end of a horizontal spring that obeys Hooked's law is attached to a wall. The spring is compressed æo = 0.400 m, and a block with mass 0.300 kg is attached to horizontal surface. Electronic sensors measure the speed v of the block after it has traveled a distance d from its initial position against the compressed spring. The measured The spring is then released, and the block moves along a O The spring force is always less than friction, so the block decelerates all the time. values are listed in the table below. Submit Previous Answers d (m) v (m/s) v Correct 0.05 0.85 0.10 1.11 Part B 0.15 1.24 0.25 1.26 Use the work-energy theorem to derive an expression for v? in terms of d. Do not substitute the value of æo into the expression. 0.30 1.14 0.35 0.90 Express your answer in terms of some…arrow_forward
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