Question

Could you help me with this question?

Answer 1

Answer:

Magnitude of static friction force is 70 sin40° = 44.99 N.  

No, it is not necessary that it is maximum static friction.

Normal force is equal to 70 cos40° = 53.62 N.

Explanation:

We apply newton law of moton equation along the plane and perpendicular to plane;

Along the plane,

70 sin 40° = $f_{r}$  ---------------(1)

70 cos 40° = N --------------(2)

$f_{r}_{max}$ = μN -----------------(3)

So, it depends on the value of μ that the friction is maximum or not .