Física preguntas y respuestas

मयाधान: \( \mathrm{E}=\frac{\mathrm{hc}}{\lambda}=\frac{6.63 \times 10^{-34} \times 3 \times 10^{6}}{3000 \times 10^{-10}} \mathrm{~J}=6.63 \times 10^{-19} \mathrm{~J}=4.14 \mathrm{eV} \) \[ \mathrm{E}_{\mathrm{k}}=\mathrm{E}-\phi=(4.14-2.3) \mathrm{eV}=1.84 \mathrm{eV} \] 02. UV radiation having a 300 mm wavelength falls on uranium metal, ejecting 0.5 cV electrons. What is the binding energy of electrons to uranium metal? (Planck's constant \( =6.63 \times 10^{-34} \mathrm{kgm}^{2} \mathrm{~s}^{-1} \) )

A body of weight \( 30 \mathrm{~kg} . \mathrm{wt} \) is placed on a rough horizontal plane. A horizontal force of magnitude Fkg .wt is applied to it, making it about to move. If the measure of the angle between the resultant reaction and the limiting friction force is \( \theta \), where \( \cos \theta=\frac{5}{13} \). find the value of the resultant reaction.

A cold piece of metal is placed into a cup of hot water. This causes the temperature of the water to fall \( 5.25^{\circ} \mathrm{C} \). The original temperature of the water was \( 62.4^{\circ} \mathrm{C} \). What is the new temperature?

6. Como a gravidade e a força centrípeta influenciam atividades do dia a dia, como andar de bicicleta em uma curva? - Relacione como a força centrípeta mantém o ciclista na trajetória curva e como a velocidade afeta essa força.

14. Seorang ilmuwan melakukan percobaan menembakkan proyektil. Proyektil ditembakkan ke udara dengan sudut tertentuterhadap horizontal, dan selama bergerak, proyektil mengikuti lintasan parabola. Ketinggian proyektil dalam \( h \) meter terhadap waktu \( t \) dalam detik setelah ditembakkan dapat dinyatakan dengan persamaan \( h(t)=-4 \mathrm{t}^{2}+16 \mathrm{t}+50 \). Jika kelajuan proyekti sepanjang sumbu horizontal sebesar \( 10 \mathrm{~m} / \mathrm{s} \), maka jarak horizontal proyektil saat ia mencapai titik maksimum diukur dari titik awal ia ditembakkan adalah .... a. 10 m b. 20 m c. 30 m d. 40 m e. 50 m

15. In an archery competition, an archer stands on a hill so that the arrow in her bow is 20.0 meters above the ground and is aimed at an angle of \( 0^{\circ} \) relative to the ground. If the archer is trying to hit a target that lies on the ground 118 m away, with what initial velocity must she launch her arrow? (NOTE: The picture is not drawn to scale.)

14. A diver is on a hill overlooking a lake. If the hill is 45 feet above the surface of the water and the liver jumps horizontally \( \left(\theta=0^{\circ}\right) \) with an initial speed of \( 20.0 \mathrm{ft} / \mathrm{sec} \), how far from the hill will the iver hit the lake?

2. De los siguientes movimientos observados durante un mismo intervalo de tiempo, ¿cuál tiene mayor aceleración y por qué? a. Un ciclista cuya rapidez pasa de \( 25 \mathrm{~m} / \mathrm{s} \) a \( 45 \mathrm{~m} / \mathrm{s} \). b. Un automóvil que parte del reposo y alcanza una velocidad de \( 72 \mathrm{~km} / \mathrm{h} \).

Un cuerpo inicia su movimiento para \( t=0 \mathrm{~s} \) en la posición \( x=5 \mathrm{~cm} \), luego alcanza la posición \( x=23 \mathrm{~cm} \) y finalmente se devuelve a la posición \( x \) \( =17 \mathrm{~cm} \). Si emplea 15 s en todo el recorrido, ¿cuál es su velocidad media?

5- [similar to Byron-Fuller 2.9] Consider the action \( I\left[\psi_{r}, \psi_{i}\right]=\int \mathcal{L} d t d x d y d z \) where \[ \mathcal{L}=\frac{\hbar^{2}}{2 m} \nabla \psi^{*} \cdot \nabla \psi+V \psi^{*} \psi-\frac{i \hbar}{2}\left(\dot{\psi} \psi^{*}-\psi \dot{\psi}^{*}\right) \] is called Lagrangian density and \( \psi=\psi_{r}+i \psi_{i}(\hbar \) and \( m \) are constants, \( V \) is a given function of \( x, y \), and \( z \), star denotes complex conjugation, and dot means \( d / \partial t) \). Show that the Euler-Lagrange equations for this action lead to the Schrödinger equation: \[ \left(-\frac{\hbar^{2}}{2 m} \nabla^{2}+V\right) \psi=i \hbar \frac{\partial \psi}{\partial t} \]