فيزياء: أي استفسار أول سؤال

[mnonna]

السلام عليكم
في سؤالين اليوم مره ماعرفت احلهم بليز ساعدوني :
1- a 5-kg box is pulled up an inclined plane (angle=30) with a horizontal force f=50 n . if the box moves with a constant speed , what is the cofficent of friction ??

2- an 80-kg box is affected by a force of 500 n with an angle of 40 with the horizontal . if the box started its motion from rest and covered 8 m in 2 sec , what is the kinetic coefficient ???

pplz help !!
thx