Askateboarder on a half-pipe changes his velocity from 6.0 m/s forwards to 4.0 m/s backward in 5.0 s. what is the acceleration of the skateboarder?

John throws .4 kg ball with velocity of 18 m/s. hits .2 kg bottle and bottle flies 25 m/s. how fast is ball traveling after hitting the bottle?

Arope has one end tied to a vertical support. you hold the other end so that the rope is horizontal. if you move the end of the rope back and forth with a frequency of 4 hz, the transverse wave you produce has a wavelength of 0.5 m. what is the speed of the wave in the rope?

While preforming an experiment involving a reaction between two chemicals the scientist observes that the reaction container has become warm the observation is an example of