Una caja de 5.0 kg de masa, rueda por unplano inclinado habiendo un coeficiente de fricción cinética 0.35 entre la caja y el plano. El plano tiene un ángulo de inclinación de 35 grados como se muestra en la figura. La magnitud de la aceleración en m/s2
de la caja en el plano es:

Pistas
..
El peso mg se descompone en dos componentes, en la dirección "x" es mg sen del ángulo y en la dirección "y" es -- mg cos del ángulo.

PlantearF neta y = 0 para calcular la magnitud de la fuerza normal y la fuerza de fricción sobre la caja:
n =- mg cos del ángulo = 0 n=? fc= cociente de fricción cinética x n=?

Aplicar la 2da ley de Newton en la dirección x y despejar a : Fneta x = -fc + mg sen del ángulo = m ax. ax=?

force is mass*acceleration.

we have a very small mass: 11.4*0.001 kg

if we want 0.035n of force, we need an acceleration:

0.035 = 11.4*0.001*a

a = 0.035/(11.4*0.001) m/s^2

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.