A spring is used to launch a block up a frictionless ramp as shown at right. At time t,, the spring is compressed and the block is released from point A. The block moves up the ramp, losing contact with the spring at point B. When it passes point C, the block has a velocity vc directed up the ramp. Imagine a system that includes the block and possibly one or more additional objects. Is it possible to choose a system whose total energy is constant during the interval from t, to t,? If so, state which object(s) must be included in the system. Explain. a. b. Is it possible to choose a system so that the total energy is not constant during the interval from t, to t,? If so, what is the system containing the fewest possible objects for which the energy is not constant during this interval? Explain

A spring is used to launch a block up a frictionless ramp as shown at right. At time t,, the spring is compressed and the block is released from point A. The block moves up the ramp, losing contact with the spring at point B. When it passes point C, the block has a velocity vc directed up the ramp. Imagine a system that includes the block and possibly one or more additional objects. Is it possible to choose a system whose total energy is constant during the interval from t, to t,? If so, state which object(s) must be included in the system. Explain. a. b. Is it possible to choose a system so that the total energy is not constant during the interval from t, to t,? If so, what is the system containing the fewest possible objects for which the energy is not constant during this interval? Explain

University Physics Volume 1

18th Edition

ISBN:9781938168277

Author:William Moebs, Samuel J. Ling, Jeff Sanny

Publisher:William Moebs, Samuel J. Ling, Jeff Sanny

Chapter7: Work And Kinetic Energy

Section: Chapter Questions

Problem 108CP: Consider a linear spring, as in Figure 7.7(a), with mass M uniformly distributed along its length....

See similar textbooks

Similar questions

A 100 — kg man is skiing across level ground at a speed of 8.0 m/s when he comes to the small slope 1.8 m higher than ground level shown in the following figure. (a) If the skier coasts up the bill, what is his speed when he reaches the top plateau? Assume friction between the snow and skis is negligible. (b) What is his speed when he reaches the upper level if an 80 — N frictional force acts on the skis?
In an iconic movie scene, Forrest Gump (https://openstaxcollege.org/l/21ForrGumpvid) runs around the country. If he is running at a constant speed of 3 m/s, would it take him more or less energy to run uphill or downhill and why?
Check Your Understanding When the length of the spring in Example 8.3 changes from an initial value of 22.0 cm to a final value, the elastic potential energy it contributes changes by 0.0800 J. Find the final length.
A 200-g steel ball is tied to a 2.00m “massless” string and hung from the ceiling to make a pendulum, and then, the ball is brought to a position making a 30 angle with the vertical direction and released from rest. Ignoring the effects of the air resistance, find the speed of the ball when the string (a) is vertically down, (b) makes an angle of 20 with the vertical and (c) makes an angle of 10 with the vertical.
In the Back to the Future movies (https://openstaxcollege.org/l/2lbactofutclip), a DeLorean car of mass 1230 kg travels at 88 miles per hour to venture back to the future. (a) What is the kinetic energy of the DeLorean? (b) What spring constant would be needed to stop this DeLorean in a distance of 0.1m?
Check Your Understanding There is a second solution to the system of equations solved in this example (because the energy equation is quadratic): v1.f=-2.5m/s , v2.f=0 . This solution is unacceptable on physical grounds; what’s with it?
An a simple pendulum swings back and forth, the forces acting on the suspended object are (a) the gravitational force, (b) the tension in the supporting cord, and (c) air resistance, (i) Which of these forces, if any, does no work on the pendulum at any time? (ii) Which of these forces does negative work on the pendulum at all Limes during its motion?
At the start of a basketball game, a referee tosses a basketball straight into the air by giving it some initial speed. After being given that speed, the ball reaches a maximum height of 4.25 m above where it started. Using conservation of energy, find a. the balls initial speed and b. the height of the ball when it has a speed of 2.5 m/s.
Consider the following scenario. A car for which friction is not negligible accelerates from rest down a hill, running out of gasoline after a short distance (see below). The driver lets the car coast farther down the hill, then up and over a small crest. He then coasts down that hill into a gas station, where he brakes to a stop and fills that tank with gasoline. Identify the forms of energy the car has, and how they are changed and transferred in this series of events.
Consider a particle on which a force acts that depends on the position of the particle. This force is given by . Find the work done by this force when the particle moves from the origin to a point 5 meters to the right on the x-axis.
Consider a linear spring, as in Figure 7.7(a), with mass M uniformly distributed along its length. The left end of the spring is fixed, but the right end, at the equilibrium position x=0 , is moving with speed v in the x-direction. What is the total kinetic energy of the spring? (Hint: First express the kinetic energy of an infinitesimal element of the spring dm in terms of the total mass, equilibrium length, speed of the right-hand end, and position along the spring; then integrate.)
A particle of mass 4.0 kg is constrained to move along the x -axis under a single force F(x)=cx3 , where c=8.0N/m3 . The particle’s speed at A, where xA=1.0m , is 6.0 m/s. What is its speed at B, where xB=2.0m ?