Two railway trucks of masses m and 3m move towards each other in opposite directions with speeds 2v and v respectively. these trucks collide and stick together. what is the speed of the trucks after the collision? a v/4 b v/2 c v d 5v/4

The correct answer is -v/4.

Explanation:

By applying equation of collision.

m1u1 + m2u2 = v(m1+m2).

The second object is moving in opposite direction so its momentum is negative. So, we have.

V= m1u1 + (-m2u2)/ m1 + m2

By imputing the data we have;

V = m×2v + (-3m×v)/ m+3m

V= 2mv - 3mv/ 4m

V = -mV/4m

V= -v/4//

NB: we have negative V because m2 is bigger than m1.

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.

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.