Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

A uniform horizontal bar of length \( 70\text{ cm} \) and mass \( 4.0\text{ kg} \) rests on two knife edges placed \( 10\text{ cm} \) from each end. A load of \( 6.0\text{ kg} \) is suspended at a distance of \( 30\text{ cm} \) from one end (closer to knife-edge \( K_1 \)). Taking \( g = 9.8\text{ m/s}^2 \), the normal reaction \( R_1 \) at knife-edge \( K_1 \) is:

1. A
   \( 54.88\text{ N} \)
2. B
   \( 98.00\text{ N} \)
3. C
   \( 43.12\text{ N} \)
4. D
   \( 68.60\text{ N} \)