Laurel is calculating the power she generated while running the 800 m race. She exerted a force of 200 N to complete the race in 150 seconds. (A) How much work did she do? (B) How much power didsshe exert? Be sure to give units, include the equations used, and show your work. You may begin your responses with: - The work she did is . . . because . . . .

A lamp hangs vertically from a cord in a descending elevator that accelerates at \( 2.4 \mathrm{~m} / \mathrm{s}^{2} \). If the tension in the cord is 89 N . The mass of the lamp in \( (\mathrm{kg}) \) is:

Ejemplo 2 Encontremos la velocidad de una bala de 0.02 kg que adquiere una energia cinética de 400 J. \( \begin{array}{lll}\text { Datos: } \\ m=0.02 \mathrm{~kg} & E_{k}=\frac{1}{2} m v^{2} \\ E_{k}=4001 & \frac{2 E_{k}}{m}=v^{2} & \begin{array}{l}\text { Despejamos la velocidad dejándola e } \\ \text { uno de los lados de la ecuación. }\end{array}\end{array} \)

(5) Ahmed pulls his little sister Noha in a sled on an iey surface (assume no friction), with a force of 60.0 N at an angle of \( 37.0^{\circ} \) upward from the horizontal. If he pulls her 12.0 m , what is the work done by Ahmed? \( \begin{array}{llll}\text { A) } 185 \mathrm{~J} & \text { B) } 433 \mathrm{~J} & \text { C) } 575 \mathrm{~J} & \text { (D) } 720 \mathrm{~J}\end{array} \)

Аанное уравнение: \[ \vec{a}=\sum_{k=1}^{n} \overrightarrow{F_{k}}+\vec{\Phi}_{e}+\vec{\Phi}_{C} \] называется: Выберите один ответ: Уравнением относительного двикения точки. Основным законом динамики относительного движения точки. Основным законом динамики линейного движения тела. Кориолисовой силой инерции.

A 10 kg crate is placed on a rough horizontal surface \( \mu_{\mathrm{k}}=0.4 \) and connected with 12 kg hanging mass via a string that passes over a massless and frictionless pully as shown in the figure beside. Thé mass ( kg ) that must be added to the crate so that the crate moves with constant velocity is: