For free falling bodies, the final velocity may be calculated through the equation,
Vf = gt
Where g is the acceleration due to gravity (9.8 m/s²) and t is the time elapsed. Substituting the known values,
Vf = (9.8 m/s²) x (4 s) = 39.2 m/s
Therefore, the object's velocity is approximately 39.2 m/s.
Brushes, battery terminals, commutator, armature, magnets
The temperature increase of a substance is T=Q/m*c, where m is the mass, Q is the energy absorbed and c is the specific heat. So you can conclude that if the lead gets to a higher temperature, it must have a lower specific heat
