Thanks for the help, but I'm still a bit stuck.
BvU, μ in the third equation is the static friction between the crates and the truck and μs is the static friction between tires and road.
The friction force between truck and crates would decrease to μmg when the crates begin sliding I believe...
Homework Statement
Two crates of mass m are stacked on the back of a flat-bed truck of mass M. The truck accelerates from rest with a uniform acceleration a.
How does the force exerted by the road on the truck change when the masses are stationary vs. when the masses are sliding on the floor of...
Yeah, if I substitute for both I get:
sin(\phi)-sin^2(\theta)sin(\phi)-cos(\phi)+cos^2(\theta)cos(\phi)
But I should probably only substitute for sin or cos so that gives me:
sin(\phi)-sin^2(\theta)sin(\phi)-sin^2(\theta)cos(\phi)
or
cos^2(\theta)sin(\phi)-cos(\phi)+cos^2(\theta)cos(\phi)...
Can someone please show me, step-by-step, how
cos(θ)sin(θ+φ)-sinθcos(θ+φ)
simplifies to sinφ?
I know I have to use trig identities, and I got to cos2θsinφ-sin2θcosφ but I'm not sure where to go from there.
Thanks