12.Two ice skaters are initially at rest. The 78.2 kg male ice skater pushes his 48.5 kg female partner forward and away from his body with a velocity of 8.46 m/s. What is the male skater's velocity as a result of the push

-5.247 m/s

Explanation:

From the law of conservation of momentum,

Total momentum before collision = Total momentum after collision

Note: Since both ice skaters were initially at rest, therefore the total momentum before collision = 0

0 = mv+m'v'

-mv = m'v' Equation 1

Where m = mass of the male skater, m' = mass of the female skater, v = Final velocity of the male skater, v' = final velocity of the female skater

make v the subject of the equation

v = -(m'v'/m) Equation 2

Given: m = 78.2 kg, m' = 48.5 kg, v' = 8.46 m/s

Substitute into equation 2

v = -(48.5×8.46/78.2)

v = -5.247 m/s.

Hence the velocity of the male skater = -5.247 m/s.

Note: The negative sign means that the direction of the velocity of the male skater is in opposite direction to that of the velocity of the female skater

there is no correct list among the choices you've provided.

the list might look something like this:

-- baby human

-- piccolo

-- flute

-- soprano singer

-- trumpet

-- tenor singer

-- trombone

-- baritone singer

-- baritone horn

-- bass singer

-- tuba

since i had to make up the list myself, i made it easy on myself, and i didn't try to shuffle the string instruments and woodwinds into it too.