Block A in the figure weighs 1.80N and block B weighs 3.80N . The coefficient of
ID: 1393701 • Letter: B
Question
Block A in the figure weighs 1.80N and block B weighs 3.80N . The coefficient of kinetic friction between all surfaces is 0.500
1)Find the magnitude of the horizontal force F? a necessary to drag block B to the left at a constant speed of 9.50cm/s if A rests on B and moves with it (figure a).
2)Find the magnitude of the horizontal force F? b necessary to drag block B to the left at a constant speed of 9.50cm/s if A is held at rest by a string (figure b).
3)In part (A), what is the friction force on block A?
Explanation / Answer
WA= 1.80 N
WB= 3.80N
mu K =0.5
1] At constant speed[ no acceleration]
F net =0N
F net= F horizontal- F kinetic
0N= F horizontal- F kinetic
F horizontal= F kinetic = muk * [WA+WB]= 2.8 N
2] here A is held at rest by a string
hence; F horizontal= F kinetic = muk * [WB]= 1.9 N
3] F friction on block A = muk*WA = 0.9 N