Hi,
I'm really struggling with this question, and just need a bit of help. My understanding of the relationships between work-energy is poor so if someone could explain why some of it works, that would be great:
A small model fire engine of mass 0.5kg is on a straight rigid plank, at angle z to the horizontal. It is projected up the plank along a line of greatest slope. Non gravitational resistance to motion is constant and has magnitude R newtons.
When z =20, initial speed = 5m/s and comes to rest after moving 2 metres. Find R to 3s.f.
I'm totally lost so any help or pointers would be really beneficial. Thanks!