Agraduated cylinder has 20 ml (cm3) of water placed in it. an irregularly shaped rock is then dropped in the graduated cylinder and the volume of the rock and water in the cylinder now reads 30 ml (cm3). the mass of the rock dropped into the graduated cylinder is 23 grams.
a.) find the volume of the rock dropped into the graduated cylinder.
b.) find the density of the rock dropped into the graduated cylinder.

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.