Asemi-circle of radius 8 cm, rocks back and forth along a line. the distance between the line on which the semi-circle sits and the line above is 12 cm. as it rocks without slipping, the semi-circle touches the line above at two points. (when the semi-circle hits the line above, it immediately rocks back in the other direction.) what is the distance between these two points, in millimetres, rounded off to the nearest whole number

Astone is thrown with a speed v0 and returns to earth, as the drawing shows. ignore friction and air resistance, and consider the initial and final locations of the stone. which one of the following correctly describes the change δpe in the gravitational potential energy and the change δke in the kinetic energy of the stone as it moves from its initial to its final location? options a.δpe = 0 j and δke = 0 j b.δpe is positive and δke is negative c.δpe = 0 j and δke is positive d.δpe is negative and δke is positive e.δpe = 0 j and δke is negative