Answer:
<em>c. because the rod polarizes the metal.</em>
Explanation:
Bringing the negatively charged rod close to the neutral metal ball causes the neutral metal ball to be polarized with induced positive charge on it. The polarizing of the formally neutral metal ball is due to the negative charge on the metal rod (bodies induce a charge opposite of their own charge on a nearby neutral body). The ball and rod then attract themselves because bodies with opposite charges attract each other, unlike bodies with same charges that repel each other.
Work is a quantity that measures the effects of a force acting over a distance.
The second one is the answer
Answer:
ΔT = 40.91 °C
Explanation:
First we find the kinetic energy of one hit to the nail:
K.E = (1/2)mv²
where,
K.E = Kinetic energy = ?
m = mass of hammer = 1.6 kg
v = speed of hammer = 7.7 m/s
Therefore,
K.E = (1/2)(1.6 kg)(7.7 m/s)²
K.E = 47.432 J
Now, for 10 hits:
K.E = (10)(47.432 J)
K.E = 474.32 J
Now, we calculate the heat energy transferred (Q) to the nail. As, it is the 59% of K.E. Therefore,
Q = (0.59)K.E
Q = (0.59)(474.32 J)
Q = 279.84 J
The change in energy of nail is given as:
Q = mCΔT
where,
m = mass of nail = 7.6 g = 0.0076 kg
C = specific heat capacity of aluminum = 900 J/kg.°C
ΔT = Increase in temperature = ?
Therefore,
279.84 J = (0.0076 kg)(900 J/kg.°C)ΔT
ΔT = (279.84 J)/(6.84 J/°C)
<u>ΔT = 40.91 °C</u>