The weightlifter lifted the barbell to a height of 2.2 m, while doing the work of 3500 J. What is the weight of the barbell?

To solve the problem, we will use the formula for mechanical work:

A = F * s, where A is mechanical work, F is the force acting on the body, s is the movement of the body under the action of the force. In our cases, the movement of the body is the height to which the bar was raised: s = h = 2.2 m. The body (bar) is affected by gravity: F = m * g.

Thus, we get:

A = F * s = m * g * h. Let us express and find from this formula the mass of the barbell:

m = A: (g * h). Substitute the values and get:

m = 3500: (10 * 2.2) = 3500: 22 = 159 2/22 = 159 1/11.

Answer: 159 1/11 kilograms.