Question

a block is placed on a rough horizontal plane three horizontal forces are applied on the block as shown in the figure if the block is in equilibrium find the friction force acting on the block

Answer 1

Answer:

It's too simple dear....

Just remember one thing friction acts always opposite to resultant force....

Break the given forces in x-y components.... You will get 100 N force in negative x-axis... And 200 N force in positive y-axis...

So friction opposes this force...

So friction is 100 N in positive x-axis and 200 N in negative y-axis...

So f = (100 i^) + ( -- 200 j^) ......

Answer 2

Answer:

Explanation:

Since the block is in equilibrium, resultant force must be zero.

Now consider ALL of the horizontal forces. These are:

1) The 300N force

2) The horizontal components of 400N and 200N forces

3) The frictional force

Along the left side of the x-axis, horizontal forces are:

400sin37 + 200sin53 = 400N

Along the right side of x-axis, horizontal forces are:

300N only

So frictional force is (400N-300N) = 100N in the direction to the right of the block since the block TENDS TO move to the left where the horizontal force is greater.