Question

A 3520 kg truck moving north makes an INELASTIC collision with an 1480 kg car moving 13.0 m/s east. After colliding, they have a velocity of 9.80 m/s at 66.9 degrees. What was the initial velocity of the truck? (m/s)

Answer 1

v = 12.8 m/s

Step-by-step explanation:

• Assuming no external forces acting during the collision, total momentum must be conserved.
• Since momentum is a vector, their components must be conserved too.
• Choosing a pair of axes coincident with the N-S and W-E directions, naming x to the W-E axis and y to the N-S one, we can write the following algebraic equations:

`p_(ox) = p_(fx) (1)`

`p_(oy) = p_(fy) (2)`

• Since we know all the information needed to solve (1), assuming a completely inelastic collision, we can focus in (2), writing both sides of the equation as follows:

`p_(oy) = m_(t) * v_(ot) = 3520 kg* v_(ot) (3)`

`p_(fy) = m_(f) * v_(fy) = 5000 kg* 9.8 m/s * sin 66.9 = 45080 kg*m/s (4)`

• Since (4) and (3) are equal each other, we can solve for vot, as follows:

`v_(ot) =(45080kg*m/s)/(3520kg) = 12.8 m/s (5)`