Daniel y Alejandro empujan una caja de forma simultanea. Alejandro la empuja hacia la derecha con una fuerza de 80N y Daniel la empuja hacia la izquierda con una fuerza de 130N. ¿Cuál será el valor de la fuerza resultante?

Am i correct on these two physics questions?

Determine the largest intensity w of the uniform loading that can be applied to the frame without causing either the average normal stress or the average shear stress at section b–b to exceed σ=19 mpa and τ=24 mpa, respectively.

During the apollo moon missions, astronauts were concerned about the effects of newton's third law of motion when: o a. they ejected waste water, because they were concerned that it would push them off course. o b. they reentered earth's atmosphere, because they were carrying heavy moon rocks. o c. they took off from earth, because a large force was required to generate large acceleration. o d. they detected incoming space debris, because the inertia of the debris could damage their ship.