The basic relationship between voltage, resistance and current of an electrical device is given by Ohm's law:
where
V is the voltage
I is the current
R is the resistance
The hot plate in our problem is connected to a source of V=120 V and it has a resistance of
, therefore we can rearrange the previous equation to calculate the current through the device:
Answer:
(B) sound/kinetic
(E) Gravitational/kinetic
(F) mechanical/sound
Explanation:
(B) the useful energy transfer is sound but a by product of that is kinetic or mechanical energy because of the vibrations needed to make sound
(E) the useful energy transfer is Gravitational potential but a by product of that is kinetic or mechanical energy
(F) the useful energy transfer is kinetic or mechanical energy but the byproduct is noise and occasionally heat
Facing disagreement forces scientists to prove their theories more conclusively.
Answer:
(a) -472.305 J
(b) 1 m
Explanation:
(a)
Change in mechanical energy equals change in kinetic energy
Kinetic energy is given by
Initial kinetic energy is 
Since he finally comes to rest, final kinetic energy is zero because the final velocity is zero
Change in kinetic energy is given by final kinetic energy- initial kinetic energy hence
0-472.305 J=-472.305 J
(b)
From fundamental kinematic equation
Where v and u are final and initial velocities respectively, a is acceleration, s is distance
Making s the subject we obtain
but a=\mu g hence
