A 135 lb plank of length 29.5 ft rests on the ground on one end; the other end rests on a frictionless roller at the top of a wall of height 15.0 ft. The center of gravity of the plank is at its center. The plank remains in equilibrium positioned at any angle equal to or greater than 70.0 degrees with the ground, but slips if the angle is less than 70.0 degrees. Find the coefficient of static friction between the plank and the ground.

The four giant gas points that are made primarily of lightweight elements are

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.

An electron in an x-ray machine is accelerated through a potential difference of 1.00 × 104 v before it hits the target. what is the kinetic energy of the electron in electron volts?