A 20-kilogram concrete block is dropped from the top of a tall building near a construction site. The block has fallen a distance of 50 meters and has a speed of 28 meters per second when it hits the ground. Calculate the work done by friction by the block as it fell.

When a 5.0kg cart undergoes a 2.2m/s increase in speed, what is the impulse of the cart

All the simple machines make work easier to do by changing the or of a force. a. size; type b. work; type c. size; direction d. type; direction

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.)