A block of mass m is pushed off with an initial speed u so that it moves up a rough plane inclined at an angle @ to the horizontal. the friction between the block and the plane is R. Deduce an expression for the velocity v of the block after it has moved a distance d along the inclined plane. Explain any additional symbols in your expression. which is correct: (1) 1/2mu^2 - mgd sin @ - Rd = 1/2mv^2 v = [ (mu^2 - 2mgd sin @ - 2Rd) / m]^1/2 (2) 1/2mu^2 - mgd sin @ - Rd = mgd sin @ + 1/2mv^2 v = [ (mu^2 - 4mgd sin @ - 2Rd) / m]^1/2 AND WHY? thank you.