Question

a man uses a roqe to haul box of weight 600N up an inclined wooden plank of effective lenght 3.0m and onto a platforn 1.0m high if indoing so, he exerts a force of 400N on the rope calculate (1) the frictional force between the case and the plank (2) the velocity ratio of the machine; (3) the mechanical advantage (4) theuseful workdone in joulesa man uses a roqe to haul box of weight 600N up an inclined wooden plank of effective lenght 3.0m and onto a platforn 1.0m high if indoing so, he exerts a force of 400N on the rope calculate (1) the frictional force between the case and the plank (2) the velocity ratio of the machine; (3) the mechanical advantage (4) theuseful workdone in joules?

Answer 1

triangle 1, up
3 hypotenuse, along plank
sqrt (8) = 2 sqrt 2, horizontal

plankward component of weight = 600 [ (2/3) sqrt 2] = 566 N
slopeward component of weight = 600 (1/3) = 200 N
(1) but we pulled with 400 N so friction force = 400-200 = 200 N
(2) velocity up/ velocity along slope = 1/3
(3) pulls with 400 and lifts 600 so 6/4 = 3/2
(4) 600 N * 1 meter up = 600 Joules

Answer 2

I don't know the answer

Answer 3

i dont understand your steps