T2= (F2) (d2) = (0.2kg) (9.8m/s²) (0.12m) = 0.2352 N-m or 0.24 N-m
Torque 1 and 2 are not equal in mathematical method. Therefore, there were errors in balancing the two loads.
APPLICATIONS A. Explain the condition below 1. It is much easier to carry a weight in your hand when your arm is at your side than it is when your arm is stretching out in front of you. Use the concept of torque to explain this effect.
* When your arm is stretching out in front of you, any weight force exerted on your hand is at right angle to the lever arm between your shoulder and hand and produces a large torque above your shoulder. On the other hand, when your arm is at your side, any weight force exerted on your hand is directed away from your shoulder and produces no torque above your shoulder.
B. Analyze the following situations. Show a diagram of the torque in each problem. Box your final answer.
1. A 15-kg child and a 25-kg child at ends of a 4m seesaw pivoted at its center. Where should a third child of 10 kg sit in order to balance the seesaw?
T1 = F1 d1 = (15 kg) (9.8 m/s²) (2 m) = 294 N-m
T2 = F2 d2 = (25 kg) (9.8 m/s²) (2m) = 490 N-m
T3 = T2 – T1 = (490 N-m) – (294 N-m) = 196 N-m
T3= F3 D 3
196 = (10 kg) (9.8 m/s²) x
196 = 98 x
196 = 98 x
2m
2m 98 98
2 = x or
2. A 300-N bag of cement is placed on a 5-m long plank 2m from one end. Two strings one at each end support the plank. How much weight must each string support? Neglect the weight of the plank.
T1= F1 d1 = (x) (2) = 2x = 2x + 3x = 5x
T2 = F2 d2 = (300-x) (3) = 900 – 3x = 900
5x= 900
5 5
X= 180 N
300 – 180 = 120 N
3. A wheel of 20-cm diameter has an axle of 2cm radius. If a force of 300 N is exerted along the rim of the wheel, what is the smallest force on the outside of the axle that will result in zero net torque?
