A student designs an experiment to demonstrate the conservation of gravitational potential and kinetic energy. She drops a wooden block from rest through a photogate 2.0 m below. If energy is conserved, how fast should the block be travelling when it passes through the photogate?

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.