Answer
a) The reading of scale is the normal force pushing upon us. This is equal to our weight as long as normal force and the force of gravity are the only forces and we are at rest or moving with constant velocity.
b) If we stand on the scale in a swimming pool for eg, there will be a buoyant force from the water pushing up on us. The scale would read smaller reading due to this buoyant force. Also the scale would read differently if we were accelerating.
Work Step by Step
a) The reading of scale is the normal force pushing upon us. This is equal to our weight as long as normal force and the force of gravity are the only forces and we are at rest or moving with constant velocity.
b) If we stand on the scale in a swimming pool for eg, there will be a buoyant force from the water pushing up on us. The scale would read smaller reading due to this buoyant force. Also the scale would read differently if we were accelerating.