A meter rule is balanced horizontally on a knife edge by a mass of 30kg long 20cm from one end . If the position of the knife edge is 18cm from the center of the rule,what is the weight of the rule

Answer 1

To balance the meter rule on the knife edge, the torque on one side of the knife edge must equal the torque on the other side.

The torque about a point is given by the formula:

Torque = Force × Distance

Let's assume the center of the meter rule is the pivot point.

On one side of the knife edge, the torque is due to the weight of the mass:

Torque1 = (30 kg) × (9.8 m/s^2) × (0.20 m)

On the other side of the knife edge, the torque is due to the weight of the meter rule:

Torque2 = Weight of the Rule × (0.18 m)

Since the meter rule is balanced horizontally, Torque1 = Torque2:

(30 kg) × (9.8 m/s^2) × (0.20 m) = Weight of the Rule × (0.18 m)

Now we can solve for the weight of the rule:

Weight of the Rule = (30 kg) × (9.8 m/s^2) × (0.20 m) / (0.18 m)
Weight of the Rule ≈ 33.33 kg

Therefore, the weight of the rule is approximately 33.33 kg.

Answer 2

mass is in kg
weight is in Newtons

Answer 3

You are correct, and I apologize for the confusion.

To find the weight of the rule, we need to multiply the mass of the rule by the acceleration due to gravity (9.8 m/s^2). The weight of an object is given by the formula:

Weight = Mass × Acceleration due to gravity

Weight of the Rule = Mass of the Rule × Acceleration due to gravity
Weight of the Rule = 30 kg × 9.8 m/s^2
Weight of the Rule = 294 N

Therefore, the weight of the rule is 294 Newtons.

Answer 4

I think you did m g before but just expressed the answer in kg. You do not have to multiply by 9.81 twice.

Answer 5

You are correct, I apologize for the error. To find the weight of the rule, we only need to multiply the mass of the rule by the acceleration due to gravity once.

Weight of the Rule = Mass of the Rule × Acceleration due to gravity
Weight of the Rule = 30 kg × 9.8 m/s^2
Weight of the Rule = 294 N

Therefore, the weight of the rule is 294 Newtons.