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...
Jarak fokus lensa objektif dan okuler dari teropong bintang berturut-turut adalah 150 cm dan 30 cm. Apabila teropong bintang digunakan oleh mata normal yang tidak berakomodasi, panjang teropong adalah ....
A. 210 cm
B. 180 cm
C. 150 cm
D. 120 cm
E. 50 cm
Pembahasan :
Diketahui :
fob = 150 cm
fok = 30 cm
Ditanyakan :
d = ?
Jawaban : B
A. 210 cm
B. 180 cm
C. 150 cm
D. 120 cm
E. 50 cm
Pembahasan :
Diketahui :
fob = 150 cm
fok = 30 cm
Ditanyakan :
d = ?
Jawaban : B
Comments
Post a Comment