Imagine a particle of mass m, constrained to move along the x-axis, subject to some specified force F(x, t). The program of classical mechanics is to deter- mine the position of the particle at any given time: x(t). Once we know that, we can figure out the velocity (\( v=\frac{dx}{dt}\) ), the momentum (p = mv), the kinetic energy ( \( T=\frac{1}{2}mv^2 \) ), or any other dynamical variable of interest. And how do we go about determining x(t)? We apply Newton's second law: F = ma. (For conservative systems the only kind we shall consider, and, fortunately, the only kind that occur at the microscopic level---the force can be expressed as the derivative of a potential energy function, \( F=-\frac{\partial V}{\partial x} \) , and Newton's law reads \( m\frac{d^2x}{dt^2}=-\frac{\partial V}{\partial x} \) .) This, together with appropriate initial conditions (typically the position and velocity at t 0), determines x(t). Quantum mechanics approaches this same problem quite differentl...
Soal Nomor 1 Anton melakukan percobaan pengukuran tebal dua pelat baja menggunakan jangka sorong, hasil pengukurannya seperti gambar berikut. Berdasarkan gambar tersebut, tebal pelat baja 1 dan baja 2 masing-masing adalah .... A. 4,75 cm dan 4,77 cm B. 4,75 cm dan 4,87 cm C. 4,85 cm dan 4,77 cm D. 4,85 cm dan 4,78 cm E. 4,85 cm dan 4,87 cm Pembahasan : Strategi: perhatikan letak angka nol nonius pada skala utamanya ( ini menunjukkan skala utama yang terbaca). Perhatikan juga skala nonius yang berimpit dengan skala utamanya (ini menjadi skala nonius yang terbaca). Pada pelat baja 1 hasil pengukurannya : x = skala utama + nonius = 4,80 cm + 0,05 cm = 4,85 cm Pada pelat baja 2 hasil pengukurannya : x = skala utama + nonius = 4,80 cm + 0,07 cm = 4,87 cm Jawaban : E
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