contestada

A proton of mass m, is accelerated along a straight line at a rate of a = 3.6 x 10^15 m/s^2 in a machine. The proton had an initial speed of v; = 2.4 x 10^7m/s and traveled for d= 0.035 m with the given acceleration. Givens: m2 = 1.67 x 10^-27 kg, a = 3.6 x 10^15 m/s^2, v; = 2.4 x 10^7m/s, d=0.035 m
(a) Use the 1D kinematic equations for constant acceleration motion to derive a symbolic expression for the speed of the proton, vi(mp, a, Vi,d), after it has traveled a distance d. (Chapter 2 physics!)
(b) Calculate a numerical value for us if d = 0.035 m.
(c) With the initial speed, Vi, taken as given, and your expression for Uf from part (a), derive a symbolic expression for the increase in the proton's kinetic energy, AK(mp, a,d). Simplify your expression as much as possible. (Hint: Your final answer should simplify to the product of three parameters.)
(d) By Newton's 2nd law the net force, F, acting on the proton must be F = mya. Rewrite your symbolic expression for AK in terms of F and d. In this form, your equation should look like a theorem from the physics of motion. What is the name of the theorem?
(e) Using your result from part (c) or from part (d), calculate a numerical value for AK
Check: If my = 1.67 x 10^-27 kg, a = 1.8 x 10^15 m/s^2, v; = 1.2 x 10^7m/s, and d = 0.050 m, then (b) 1.8 x 10^7m/s, (e) 1.5 x 10^-13 J.

Respuesta :

Answer:

a) [tex]v_{f}=\sqrt{v_{o}^{2}+2\cdot a \cdot d}[/tex], b) [tex]v_{f} = 2.877 \times 10^{7} \,\frac{m}{s}[/tex], c) [tex]\Delta K = m \cdot a \cdot d[/tex], d) [tex]\Delta K = F \cdot d[/tex], e) [tex]\Delta K = 2.104 \times 10^{-13}\,J[/tex]

Explanation:

a) The final speed of the proton after travelling a distance is given by this formula:

[tex]v_{f}^{2} = v_{o}^{2} + 2 \cdot a \cdot d[/tex]

[tex]v_{f}=\sqrt{v_{o}^{2}+2\cdot a \cdot d}[/tex]

b) The numerical value is:

[tex]v_{f} = \sqrt{(2.4\times 10^{7}\,\frac{m}{s})^{2}+2\cdot (3.6 \times 10^{15}\,\frac{m}{s^{2}})\cdot (0.035 m) }[/tex]

[tex]v_{f} = 2.877 \times 10^{7} \,\frac{m}{s}[/tex]

c) The change of kinetic energy is modelled after the Work-Energy Theorem:

[tex]\Delta K = \frac{1}{2}\cdot m \cdot (v_{f}^{2}-v_{o}^2)[/tex]

[tex]\Delta K = m \cdot a \cdot d[/tex]

d) The previous expression is re-written as follows:

[tex]\Delta K = F \cdot d[/tex]

e) The numerical value is:

[tex]\Delta K = (1.67 \times 10^{-27} \, kg)\cdot (3.6 \times 10^{15}\,\frac{m}{s^{2}} )\cdot (0.035\,m)[/tex]

[tex]\Delta K = 2.104 \times 10^{-13}\,J[/tex]