First body:
Second body:
From description of the task we have:
Answer:
A. using a weak hydrochloric acid solution and whole pieces of chalk
Explanation:
The higher the concentration, and the greater the surface area, the faster the reaction.
Therefore, a weak acid with whole pieces of chalk is going to have the slowest rate.
The frictional force is given by
where m is the mass of the puck,
and
is the dynamic coefficient of friction.
The work done by this force to stop the puck is
where
is the total displacement of the puck.
The initial kinetic energy of the puck is
with v being the puck initial velocity. The puck comes to rest after 12 m, this means it loses all its kinetic energy, and for the principle of conservation of energy this loss of energy is equal to the work done by the frictional force. So we can write
and from this we can find the inizial velocity of the puck: