When a certain horizontal spring is stretched a distance 10 cm, it exerts a restoring force of magnitude f = 20 n. the work done by a person in stretching this spring from x = 0 to x = 10 cm is

Suppose a soccer ball is kicked from the ground at an angle 20.0º above the horizontal at 8.00 m/s. the y-velocity is determined to be 2.74 m/s. how long will the ball be in the air? assume the ball lands at the same height at which it was kicked.

Select the correct answer. what does the process of natural selection involve?

Adolphin emits ultrasound at 100khz and uses the timing of reflections to determine the position of objects in the water. part a what is the wavelength of this ultrasound? assume that temperature of water is 20 degrees c. answer in cm