I think the answer is D the 30 kg sofa
Answer:
It compares the the difference between a radioactive element remaining in specimen to the amount of the radioactive element that would have been originally trapped in the specimen. This is done by comparing the ratio of the relative abundance of this radioactive element to its non radioactive isotope in nature to their ratio remaining in the specimen and comparing it to the half-life of the radioactive isotope.
Explanation:
It is given that,
When the front wheels are over the scale, the weight recorded by the scale is 5800 N, F₁ = 5800 N
When the rear wheels are over the scale, the scale reads 6500 N, F₂ = 6500
The distance between the front and rear wheels is measured to be 3.20 m, x₂ = 3.2 m
We need to find the location of center of mass behind the front wheels. Let the center of is located at a distance of x₁. Thus balancing the torques we get :

On solving the above equation we get, x₂ = 1.69 m
So, the center of mass is located at a distance of 1.69 meters behind the front wheels.
Loud sounds ... d) willl be answer