A25,000 kg traveling east collides with a 2,000 kg truck standing still on the tracks. after the collision the train and truck are moving together at 22.3 m/s. how fast was the train going to begin with? assume there is no friction. my frame of reference sets east a positive

24.084 m/s

Explanation:

From the law of conservation of linear momentum

Total momentum before collision equals to the total momentum after collision

Since momentum=mv where m is mass and v is velocity

where is the mass of the truck, is velocity of the truck, is the common velocity of moving and standing truck after collision and is the mass of the standing truck

Making the subject we obtain

Substituting as 25000 Kg, as 22.3 m/s, as 2000 Kg we obtain

Therefore, assuming no friction and considering that after collision they still move eastwards hence common velocity and initial truck velocities are positive

The truck was moving at 24.084 m/s

i don't know that i agree with that but what's the question ?

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)