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A 10-kg iron ball is dropped onto a pavement from a height
Chapter 9, Problem 7P(choose chapter or problem)
A 10-kg iron ball is dropped onto a pavement from a height of 100 m. If half of the heat generated goes into 3 warming the ball, find the temperature increase of the ball. (In SI units, the specific heat capacity of iron is 450 J/kg°C.) Why is the answer the same for a ball of any mass?
Questions & Answers
QUESTION:
A 10-kg iron ball is dropped onto a pavement from a height of 100 m. If half of the heat generated goes into 3 warming the ball, find the temperature increase of the ball. (In SI units, the specific heat capacity of iron is 450 J/kg°C.) Why is the answer the same for a ball of any mass?
ANSWER:Solution 7P In this case the heat generated by the ball comes from the potential energy of the ball. Step 1 The potential energy of the ball is given by E P mgh Where m is the mass of the ball, g is the acceleration due to gravity and h is the height of the ball. From the given question we know that m = 10 kg g = 9.8 m/s2 h = 100 m 2 So the potential energy ispE = (10 kg)(9.8 m/s )(100 m) = 9800 J Half of the energy will be used to increase the temperature. Hence the energy that will be used to increase the temperature is 9800 J Q = 2 = 4900 J