Aconstant horizontal force acts within an xy-coordinate system to move a 2.2 kg package across a frictionless surface starting at t=0.
given that v_sub_0x = 2.23 m/s, v_sub_fx = 10.86, v_sub_0y = 1.97, v_sub_fy = -12.04 and t_sub_f = 2.76s, find the magnitude of the constant force. note that the subscript "f" means "final."

How would you place two electrons on a sphere of radius r so that the electrostatic potential energy is minimized. how would you place three electrons to solve the same problem.

The period of a pendulum varies directly as the square root of the length of the pendulum and inversely as the square root of the acceleration due to gravity. find the period when the length is 144 cm and the acceleration due to gravity is 980 cm per second squared, if the period is 7pi seconds when the length is 289 cm and the acceleration due to gravity is 980 cm per second squared.

Suppose that 27 j of work is needed to stretch a spring from its natural length of 6 m to a length of 9 m. (a) how much work is needed to stretch the spring from 12 m to 14 m? j (b) how far beyond its natural length will a force of 78 n keep the spring stretched?