It’s physical something you can physically do
The velocity of the girl is -4.8 m/s.
Using the principle of conservation of linear momentum, The total momentum of bodies before and after collision is constant. Since the two objects are stationary, the initial momentum of each body is zero.
Thus;
0 = (80 × 3) + (50 × v)
0 = 240 + 50 v
-240 = 50 v
v = -240/50
v = -4.8 m/s
Note that the negative sign shows that the velocity of the girl is in opposite direction that that of the girl.
Learn more about momentum: brainly.com/question/904448
The mass of this bag of cement in S.I. units (kg) is equal to 0.062 kilograms.
<u>Given the following data:</u>
- Mass of cement = 62 grams.
To calculate the mass of this bag of cement in S.I. units (kg):
<h3>How to convert to
S.I. units.</h3>
In Science, kilograms (kg) is the standard unit of measurement or S.I. units of the mass of a physical object. Thus, we would convert the value of the mass of this bag of cement in grams to kilograms (kg) as follows:
<u>Conversion:</u>
1000 grams = 1 kilograms.
62 grams = X kilograms.
Cross-multiplying, we have:
X = 
X = 0.062 kilograms.
Read more on mass here: brainly.com/question/13833323