Answer:
38.75N
Step-by-step explanation:
According to Newton's second law
\sum Fx = ma
Fm-Ff = ma
Fm is the moving force
Fm = mgsin theta
Fm = 15(9.8)sin38
Fm = 90.5N
Ff is the frictional force
m is the mass = 15kg
a is two acceleration
Get the acceleration
a= F/m
a = 52/15
a ,= 3.45m/s²
Substitute the given values into the formula
90.5-Ff = 15(3.45)
90.5-Ff = 51.75
Ff = 90.5-51.75
Ff = 38.75N
Hence the frictional force on the box is 38.75N