Please answer both questions. Five identical keys are suspended from a balance w
ID: 1791418 • Letter: P
Question
Please answer both questions. Five identical keys are suspended from a balance which is held horizontally as shown. The two keys on the left are attached to the balance 6 cm from the pivot and the three keys on the right are attached 5 cm from the pivot What will happen when the person lets go of the balance beam? If the beam is not in balance, which positioning of the keys will put it in balance? An angler balances a fishing rod on her finger as shown. 2 If she were to cut the rod along the dashed line, would the weight of the piece on the left-hand side be () greater than, Ci) less than, or (Hi) equal to the weight of the piece on the right-hand side?Explanation / Answer
Moments about pivot are:
clock wise = 5cm x 3 g = 15 gm cm
anticlock wise = 6cm x 2 gms = 12 gm cm
If we move 2 keys on left to make left arm 7.5 cm the moment will become 15 gmcm and hence balance will result
The angler has balanced the rod on finger at dashed line ,hence moments of left side and equal to the moments of the right side of finger. Notice that mass on the left side is distributed at very short distance from the finger compared to the right side. Hence Weight of left side has to be greater than weight on right side so that the lesser moment arm is compensated by extra weight.