How long does it take for light to travel through matter in m/s

Which example has gravitational potential energy? a.a horse slowing down from a run b.an apple about to fall from a tree branch c.a bicycle being pedaled down a horizontal path d.beaker sitting on the floor

Karen is running forward at a speed of 9 m/s. she tosses her sweaty headband backward at a speed of 20 m/s. the speed of the headband, to the nearest whole number relative to a stationary observer watching karen

Within a pendulum, as potential energy decreases, energy increases. a. heat b. kinetic c. frictional d. gravitational