Question

a solid block is cooled by forces F1 equal to 20 Newton and F2 equal to 10 Newton respectively find the magnitude and direction of force of static friction if the limiting force of friction is equal to 20 Newton between block and floor​

Answer 1

REF. Image.
Force on block 2 kg
T−1−f
1
​
=2a...(1)
Force on block 3 kg
8−T−b
2
​
=3a...(2)
eq (1)+(2)
T−1−f
1
​
+8−T−f
2
​
=5a
7=(f
1
​
+f
2
​
)=5a
___________________
T−1−f
1
​
=2a a = 0
T−1−1=0
T=2N
​

To cease the motion
bock of 3 kg will
provide 6 N friction
& 2 kg block will provide
1 N friction
So, F
2
​
=6N
F
1
​
=