Física preguntas y respuestas

28.11. Un alambre largo y recto está a lo largo del eje \( z \) y conduce \( u \) corriente de 4.00 A en la dirección \( +z \). Determine el campo magnétic (magnitud y dirección) producido en los siguientes puntos por un seg mento de 0.500 mm del alambre con centro en el origen: a) \( x=2.00 \mathrm{~m} \), \( \begin{array}{l}y=0, z=0 ; b) x=0, y=2.00 \mathrm{~m}, z=0 \\ 2.00 \mathrm{~m}, z=0 ; d) x=0, y=0, z=2.00 \mathrm{~m} \text {. }\end{array} \)

\( b= \) Expresar 40 kgf en N

(b.) student : (1) My Day 9. An airplane starts from rest and accelerates at a constant rate of \( 3.00 \mathrm{~m} / \mathrm{s}^{2} \) for 30.0 s before leaving the ground. a. How far did it move? b. How fast was it going when it took off? 10. A brick is dropped from a high scaffold. a. What is its velocity after 4.0 s ? b. How far does the brick fall during this time? 11. A tennis ball is thrown straight up with an initial speed of \( 22.5 \mathrm{~m} / \mathrm{s} \). It is caught at the same distance above the ground. a. How high does the ball rise? b. How long does the ball remain in the air?

Arus listrik sebesar 5 mA mengalir pada suatu kawat penghantar selama 0,1 sekon. Berapa besar muatannya ?

ถ้า \( \overrightarrow{\mathrm{C}}=\overrightarrow{\mathrm{A}}+\overrightarrow{\mathrm{B}}, \overrightarrow{\mathrm{D}}=\overrightarrow{\mathrm{A}}-\overrightarrow{\mathrm{B}} \) และขนาดของ \( \overrightarrow{\mathrm{A}}, \overrightarrow{\mathrm{B}} \) และ \( \overrightarrow{\mathrm{C}} \) มีค่าเท่ากับ 5 นิวตัน, 7 นิวตัน และ 10 นิวตั ตามลำดับ จงหาขนาดของ \( \overrightarrow{\mathrm{D}} \)

A block weighing 500 N is at the point of just starting to move down a rough inclined plane when supported by a force of 200 N acting parallel to the plane in an upward direction. The same block, on the same rough inclined plane, is on the verge of moving up the plane when pulled by a force of 300 N acting parallel to the plane. Compute the inclination of the plane and the coefficient of friction between the inclined plane and the block.

\( \left. \begin{array} { c } { L = L _ { 0 } \sqrt { 1 - \frac { v ^ { 2 } } { c ^ { 2 } } } } \\ { = 90 \sqrt { 1 - \frac { ( 0.8 C ) ^ { 2 } } { ( 3 \times 10 ^ { 8 } ) ^ { 2 } } } = 54 m } \end{array} \right. \)

In one of the processes on the production line at a Sugar Mill, a quantity of gas occupying an original volume of \( 1500 \mathrm{dm}^{3} \) and at an original temperature of \( 300^{\circ} \mathrm{C} \) is expanded adiabatically to a temperature and pressure of \( 135^{\circ} \mathrm{C} \) and 200 kPa respectively. After this adiabatic expansion the gas is heated at constant volume until a pressure of 300 kPa is reached. Given: \( \mathrm{R}=0.286 \mathrm{~kJ} \cdot \mathrm{~kg}^{-1} \cdot \mathrm{~K}^{-1} ; \quad \mathrm{C}_{\mathrm{p}}=1.001 \mathrm{~kJ} \cdot \mathrm{~kg}^{-1} \cdot \mathrm{~K}^{-1}, 1 \mathrm{dm}=10^{-1} \mathrm{~m} \) Assist the production supervisor to: 1.1 Draw a fully labelled \( \mathrm{P}-\mathrm{V} \) diagram for this multi-process system. 1.2 Find the mass of the gas and pressure of the gas before the adiabatic expansion process. 1.3 Find the final volume and final temperature after both processes. 1.4 Find the specific work and specific heat transferred after both processes.

Per stimare lo spessore di una moneta da 10 centesimi di misura con un righello l'altezza della pila di monete ot- tenuta. La misura e e \( (2,9 \pm 0,1) \mathrm{cm} \), dove \( 0,1 \mathrm{~cm} \) è la sen- sibilità del righello. - Stima lo spessore della moneta. \( \quad[(1,93 \pm 0,07) \mathrm{mm}] \)

19. Ordina Tre automobili accelerano mentre percorrono un tratto rettilineo di strada: auto 1: passa da \( 25 \mathrm{~m} / \mathrm{s} \) a \( 35 \mathrm{~m} / \mathrm{s} \) in 10 s auto 2: passa da 0 a \( 30 \mathrm{~m} / \mathrm{s} \) in 15 s auto 3: passa da \( 32 \mathrm{~m} / \mathrm{s} \) a \( 12 \mathrm{~m} / \mathrm{s} \) in 5 s Ordinale per accelerazione crescente.