Physics Help Please?!?

Question

An 70.0-N crate of apples sits at rest on a ramp that runs from the ground to the bed of a truck. The ramp is inclined at 20.0°to the ground.

(a) The interaction partner of this normal force has what magnitude and direction?
Magnitude ____ N
Direction ___° below the horizontal

(b) What is the static frictional force exerted on the crate by the ramp?
___N

(c) What is the minimum possible value of the coefficient of static friction? ____

(d) The normal and frictional forces are perpendicular components of the contact force exerted on the crate by the ramp. What is the magnitude and direction of the contact force?
Magnitude ____N
Direction ___° above the horizontal

Answer 1

Lt's see
W=mg=70.0N (small tiny crate just over 7 kg)

a)
What is 'interaction partner '?

The normal force is
N=Wcos(20)

b) Action = reaction then

f=F=Wsin(20)

c)
f=uN=F
u=F/N=Wsin(20)/ [Wcos(20)]=
u=tan(20)

d) What ?
Normal force by definition is force exerted by crate on the ramp while contact force is opposing force exerted by ramp against the normal force.

90-20=70 above horizontal.

Sloppy questions will get you sloppy answers.

have fun.