Question

a block slides down a rough inclined plane of slope angle theta with a constant velocity.it is then projected up the same plane with an initial velocity v

Answer 1

block moves down the plane with constant velocity it means net force is zero...

force due to friction (f) = mgsin@ (@ is the angle of plane)

net retardation force when body is projected upward is (f+mgsin@)

f = mgsin@ so

net retardation force = 2mgsin@

ma = mgsin@

a(retardation) = 2gsin@ .............1

V2 = U2 - 2aS

finally velocity becomes 0 so

U2 = 2aS

S = U2/2a

=u2