Answer:
The frequency of vibration will be unchanged.
Explanation:
The frequency of oscillation of a simple pendulum is given by
where, 
is the acceleration due to gravity and 
is the length of the pendulum.
It can be seen from the formula that the frequency of the pendulum is independent of the mass.
Thus, the frequency of vibration will be same.
A) His wagon will accelerate more.
B) His wagon will accelerate less. Both parts are answered by F=ma. Mass is inversely proportional to acceleration, and force is directly proportional to acceleration.
Newton's third law is: For every action, there is an equal and opposite reaction. The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object.
By heat or change in matter,
there can be different reactions that create heat (like exothermic or endothermic reactions)
or movement can give off energy too,
energy is basically just heat
