A soccer ball of radius 0.11 m is moving horizontally across a rough field with a…
PHYSICS · Multi-part · CBSE · Physics · System of Particles and Rotational Motion · System of Particles and Rotational Motion
Problem
A soccer ball of radius 0.11 m is moving horizontally across a rough field with a center-of-mass speed of 2.0 m/s. At the same time it has back-spin such that its angular speed is 36 rad/s (so that Rω=4.0m/s). The ball therefore slips on the grass rather than rolling purely.
Respond to the following prompts without performing detailed numerical calculations.
(a) State the direction of the kinetic-friction force acting on the ball at the point of contact immediately after the situation described begins.
(b) Explain qualitatively how the translational speed and the angular speed of the ball each change while slipping continues.
(c) At an instant when the translational speed has decreased to 1.0 m/s, determine whether the ball is still slipping. Justify your answer.
(d) Indicate the sign (positive, negative, or zero) of the torque due to friction about the ball’s center of mass during the slipping interval and relate this to the change in its rotational kinetic energy.