Search 81,896 tutors
Ask a question
0 0

What's the net force?

A person pushes a block of mass M=6.0 kg with a constant speed of 5.0 m/s straight up a flat surface inclined 30 degrees above the horizontal. The coefficient of kinetic friction between the block and the surface is μ=0.40. What's the net force acting on the block?
Answer: 0 N
Tutors, please sign in to answer this question.

2 Answers

Check the question again. I think the following is the intent of the question:
Force due to wt of block acting downward along the inclined surface = 6 x 10 sin(30) = 30N
Force due to friction acting downward along the inclined surface = 0.4 x 6 x 10 cos(30) = 20.78N
Net force acting downwards ~ 30 + 20 = 50N
If external force applied = 50N then block will be stationary
In order for the block to move exyternal force must be more than 50N. Once the block begins to move a constant 50N of force will be required to keep the blcok moving with a constant speed.