A condition of the law of conservation of momentum is that no external forces are at play. Look at each of the following situations and choose if the law applies to it. Select all that apply.
Two cars collide on a dirt road where the force of friction is high
A bullet strikes a wooden block, causing the block to accelerate from rest.
O A coin sliding on a table experiences a frictional force.
Two kinetic carts collide on a frictionless surface.

grav force prop 1/r squared 2r all squared is 4rsquared 1/4rsquared quartered

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.