Answer:
4777.28 N
Explanation:
The gravitational force down the slope is given by the formula;
(mass *g * sin θ )
where;
θ is the angle of inclination of the slope
g is the gravitational pull
We plug in the given values into the above expression;
(4,000 x 9.8 x sin 7) = 4777.28 N.
The frictional force must equal to 4777.28 N (pointing up the slope).