Serena is mixing a material into a beaker filled with liquid. she notices that the material seems to disappear into the liquid. what physical property of the material is serena most likely observing

Abatter hits a 0.140-kg baseball that was approaching him at 30 m/s and, as a result, the ball leaves the bat at 40 m/s in the reverse of its original direction. the ball remains in contact with the bat for 2.0 ms. what is the magnitude of the average force exerted by the bat on the ball?