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**1. The problem statement, all variables and given/known data**

A truck with a heavy load has a total mass of 7500 kg. It is climbing a 15 degree incline at a steady 15 m/s when, unfortunately, the poorly secured load falls off! Immediately after losing the load, the truck begins to accelerate at 1.5 m/s 2 . What was the mass of the load? Ignore rolling friction.

**2. Relevant equations**

ΣF = Fg + n + F1 = ma , where n is the normal force and F1 is the parallel force

**3. The attempt at a solution**

Before the load falls off we know a = 0 therefore

ΣF = Fg + n + F1 = 0

Fg before fall = 9.81 m/s^2 * 7500 kg = 73575 N

Fg

_{x}before fall = -73575*Sin(15) = -19042

Because ΣFx = 0 before fall, Fg

_{x}= -F1

_{x}

=> F1

_{x}= 19042 N

After fall we have:

Fx = 19042 + Fgx = FgSin(15) = m*1.5

Fy = 0

I'm not sure where I need to go from here. I need to find m so I can find the difference, but I can't do this without either the magnitude of Fg or Fgx. Not sure how I can find these...