Um avião, após deslocar-se 120 km para nordeste (NE), desloca-se 160 km para sudeste (SE). Sendo um quarto de hora o tempo total dessa viagem, o módulo da velocidade vetorial média do avião, nesse tempo, foi de A) 320 km/h. B) 480 km/h. C) 540 km/h. D) 640 km/h. E) 800 km/h.

E) 800 km/h

Explanation:

The computation of the average vector velocity module of the plane, at that time is shown below:

The displacement vector is

d^2 = d1^2 + d2^2

where,

d1 = northeast displacement

d2 = southeast displacement

Now

d^2 = (120)^2 + (160)^2

= 14400 + 2560

= 40000

= √40000

d = 200 km

Now the average velocity is

V = ΔS ÷ Δt

= 200 ÷ 1 ÷ 4

= 200 × 4

=  800 km/h

A. True

Explanation:

We are talking about motion of solid, liquid and gas particles.

Now, for gas particles, due to the fact that it's particles are far apart from one another, it usually vibrates and thus moves freely at speeds that are higher than those of liquids of solids. For liquids, their particles are not as far apart as those of gases and so they vibrate, move about, and then slide past each other while solids are the most densely packed and so they vibrate but do not move from one place to the other like gases and liquids.

Thus, we can see that particles of liquid are more closely packed than gases and as such don't have same movement speed.