Answer:
C. 2.5 N
Explanation:
The sum of downwards moments equals sum of moments upwards
Downwards moments
Moments= Force*distance
= [10/100 * 2 ] +[20/100*4]
=[0.1*2] +[0.2*4]
=[0.2+0.8]
= 1.0 N
Equate this answer to upward force ;
1.0 N = 0.4 *U
1/0.4 =U
2.5 N =U
