Sebuah papan mempunyai ukuran panjang 4 m, lebar 30 cm, dan tebal 25 mm. Volume papan tersebut adalah A. 3 m B. 0,3 m C. 0,03 m D. 0.003 m
Answer (3)
m 1 = 2 m 2 = 3 v 1 = 4 v 2 = 1 v =speed after collision (to be determined) .
The momentul of the system preserves:
m 1 v 1 − m 2 v 2 = ( m 1 + m 2 ) v ⇒ v = m 1 + m 2 m 1 v 1 − m 2 v 2 .
Ok, we found the speed after the collision. Now, because the impact is plastic, it produces heat, sound energy and who knows what other forms of energy. We denote all this wasted energy with E .
Now, we write the energy conservation law:
2 m 1 v 1 2 + 2 m 2 v 2 2 = 2 ( m 1 + m 2 ) v 2 + E
From the above equation, you find E , and then conclude that the sound energy can certainly not be greater than this.
The maximum sound energy released cannot be greater than 15 J, after calculating the initial and final kinetic energies during the collision. The correct answer is option C) 15 J.
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DitanyaPanjang 4 mLebar 30 cmTebal 25 mmDitanyaVolumeDijawab30 cm = 0,3 m25 mm = 0,025 mVolume[tex] = 4 \times 0.3 \times 0.025 \\ = 1.2 \times 0.025 \\ = 0.03m {}^{3} [/tex]KesimpulanMaka jawabannya C.
