In order to weigh a boy in the lab. A uniform plank of wood AB 3m long having a mass of 8kg is pivoted about a point 0.5m from B in order to balance the plank horizontally. Calculate the mass of the boy.
Very useless, I thought I will get an answer
I support you, there is no answer, this site is a waste
Answer to the question
The question is not even correct
I think Zainab made a mistake
Una no get experts wey dey solve question for person?
Please I have not seen answer to the question
To calculate the mass of the boy, we need to understand the principle of moments. The principle of moments states that for an object to be in rotational equilibrium, the sum of the clockwise moments must be equal to the sum of the anticlockwise moments.
In this scenario, the clockwise moment is caused by the mass of the plank, and the anticlockwise moment is caused by the mass of the boy. We can set up an equation using the principle of moments to find the mass of the boy.
First, let's identify the known quantities:
- Length of the plank, AB = 3m
- Mass of the plank = 8kg
- Distance from the pivot point to point B = 0.5m
Let's assume the mass of the boy is m.
The moment of an object is given by the mass of the object multiplied by its distance from the pivot point. In this case, the plank's moment is 8kg multiplied by 0.5m, which is equal to 4kg*m.
Since the plank is balanced horizontally, the sum of the clockwise and anticlockwise moments must be zero:
Clockwise moment = 4kg*m
Anticlockwise moment (caused by the boy) = m * (3m - 0.5m) = m * 2.5m = 2.5m^2 kg
Using the principle of moments: Clockwise moment = Anticlockwise moment, we can write the equation:
4kg*m = 2.5m^2 kg
Now, we can solve the equation to find the mass of the boy:
Divide both sides of the equation by 2.5m^2 kg:
m = 4kg / 2.5m^2 kg
m ≈ 1.6 kg
Therefore, the mass of the boy is approximately 1.6 kg.