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Browsing Animations: Forces
8 Animations
bppb6.iwp
The animation shows a spherical object falling through a fluid with acceleration a = (k/m)v-g. The positive direction is up. The object has an intial position of 0 and is released from rest. The given inputs are for an iron ball of half a milimeter radius falling in glycerol at a temperature of 22 Degrees C. The distance from the initial position of the ball to the bottom of the cylinder is 0.50 m.
fallcompare-template.iwp
Simulation of two objects falling from rest in a gravitational field. They experience air drag proportional to the square of the speed. The vertical acceleration is given by: a = -g+kv^2, where k is termed the drag factor. The objects may be assigned different drag factors. The green ball is A; the red ball B. The vertical separation of the balls at any time is provided as one of the outputs.
incplane-template.iwp
An object slides down an inclined plane. The angle of inclination of the plane and the coefficient of kinetic friction may be adjusted.
incplane04.iwp
An object slides down an inclined plane under the influence of gravity and kinetic friction. The plane makes an angle of 30 degrees with the horizontal.
leaf.iwp
The physical situation for this problem is like that of the falling leaf where the leaf experiences a lift force that is proportional to and perpendicular to its velocity. In this case, we treat the leaf as if it were a particle, even though we know that its shape is essential to the drag force that it experiences. Unlike the falling leaf problem, we include the option of a non-zero initial velocity. Both the magnitude and direction of this velocity can be entered. The acceleration of the particle at any time is given by: a = -jg + j(k/m)v, where a and v are understood to be vectors in the complex plane (phasors). It is intended that you use your knowledge of the equations x(t) and y(t) for this motion in order to do the following problems. While the equations that you derived for homework assume Vo=0, your knowledge of the forces involved should help in doing the problems. For each path, record the inputs that you use: lift coefficient (k), mass (m), g-field (g), initial speed (Vo), initial angle (theta). Explain, with reference to the equations of motion and/or the forces why those inputs work. Use force diagrams to improve your explanations. Example problem: Make the object move in a straight vertical line. Solution: This will occur if gravity is the only force acting and the initial velocity is zero. Change the lift coefficient and the initial speed to 0. Play the animation. Make the object move in the following paths: 1. parabolic 2. complete circle at constant speed 3. constant speed along the x-axis (with non-zero lift and g) 4. cycloid totally in quadrant IV 5. cycloid totally in quadrant I 6. looping (but not circular) 7. any path with portions in both quadrants I and IV One more problem: Describe another physical situation in which the mathematics is identical to the previous situation but for which the forces are different in nature. Make it clear why the mathematics is identical to that of the previous situation.
mass-bppb-3.iwp
The animation allows you to check your calculated results against your measured results for a sphere falling through a fluid. Begin by entering your measurements in Input boxes. For the mass of the ball, enter the value that you calculated. The motion of the red ball uses the theoretical equation for position as a function of time. This assumes laminar flow and uses the mass that you calculated. The motion of the blue ball is the same as what you measured directly using distance and time of fall. Under Outputs, the Separation is the vertical distance between the blue and red balls. If you calculated mass correctly, the Separation should always be 0 or very nearly so.
stopblock01.iwp
An object moving horizontally is slowed by a force of kinetic friction. Adjust the initial velocity so that the right side of the block stops at the right-hand edge of the screen.
turntable04.iwp
A turntable accelerates uniformly. Three discs are held in place by static friction. In what order will the discs break free?