Sound waves are ___ waves & must have a medium to travel through

Sound waves are longitudinal  waves & must have a medium to travel through

they should be similar or the same

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards