Need an explanation . brainliest will be awarded.

We're adding two vectors here.  The first is 300 Newtons to the right, which we can write as (300, 0), meaning 300 to the right, 0 up.

The second is 300 at let's say a 45 degree angle down.  For the components we have an isosceles right triangle with hypotenuse 300, so the components are both magnitude 300/√2 = 150√2.  So we can write this vector (150√2, -150√2), the negative sign because it points down in the y direction.

Adding is componentwise.  The resulting force is (300+150√2, -150√2).

That has square magnitude

r² = (300+150√2)² + (-150√2)² = 150² ( (2+√2)² + (√2)² )

= 150²( (6 + 4√2) + 2)

= 300²(2+√2)

so

r = 300 √(2+√2) Newtons

That's the answer; I'm not sure if your class expects a calculator approximation, which is 554.3 Newtons.

b

explanation:

bc its just b

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