The force an ideal spring exerts on an object is given by fx = -kx, where x measures the displacement of the object from its equilibrium (x = 0) position. if k = 60 n/m, how much work is done by this force as the object moves from x = -0.20 m to x = 0?

Mike walks 100 meter north, then walks 30 meters south. after this, he walks another 10 meters north. what is the magnitude of his total displacement during this walk, in meters?

When a vertical beam of light passes through a transparent medium, the rate at which its intensity i decreases is proportional to i(t), where t represents the thickness of the medium (in feet). in clear seawater, the intensity 3 feet below the surface is 25% of the initial intensity i0 of the incident beam. what is the intensity of the beam "10" feet below the surface? (give your answer in terms of i0. round any constants or coefficients to five decimal places.)

Calculate the first and second velocities of the car with four washers attached to the pulley, using the formulas v1 = 0.25 m / t1 , and v2 = 0.25 m / (t2 – t1) where t1 and t2 are the average times the car took to reach the 0.25 and the 0.50 meter marks. record these velocities, to two decimal places, in table e.