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A piece of iron block moves across a rough horizontal surface before coming to rest. The mass of the block is 1.3 kg, and its initial speed
Question
A piece of iron block moves across a rough horizontal surface before coming to rest. The mass of the block is 1.3 kg, and its initial speed is 4.0 m/s. How much does the block’s temperature increase, if it absorbs 71% of its initial kinetic energy as internal energy? The specific heat of iron is 452 J/(kg · °C).
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Physics
3 years
2021-08-31T00:33:02+00:00
2021-08-31T00:33:02+00:00 1 Answers
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Answer:
0.0126°C
Explanation:
Kinetic energy sustain by the block,K.E = 1/2× mass×velocity^2
K.E = 1/2 ×1.3×(4^2)
=1/2 × 1.3× 16 = 1.3 ×8 = 10.4J
The internal energy is 71% of kinetic energy is;
U= 71/100 × 10.4 = 7.38J
But U = m × C × ∆T
Where U is internal energy
m is the mass of iron
C is the heat capacity of iron
∆T is the temperature change
By make ∆T the subject of the formula we have
∆T=U/ m×C
=7.38/ 1.3×452= 0.0126°C