Physics: How much work does a weightlifter do when she moves a 100 kg weight 1.5 m?

How much work does a weightlifter do when she moves

25jzaldivar

26.01.2022

Explanation:

Given that,

Mass the weight lifter want to lift is 100kg

M = 100kg

And the lifter will raise it to height of 1.5m

h = 1.5m

We want to find the work done by the lifter.

The workdone by the lifter is the gravitational potential work

The workdone by lifting a body is calculated using

Work done. = force × distance

In this case, the force is the weight of the body and it is calculated using

W = mg

Where g = 9.81m/s²

The distance is the height the body is raise

Then,

The work done becomes

W = mgh

W = 100 × 9.81 × 1.5

W = 1471.5 J

0,0(0 оценок)

123niikee

15.01.2023

$v = \sqrt{\frac{1.1g}{(1 + \frac{1}{r^2})}}$

Explanation:

By the law of energy conservation, the potential energy can be converted to kinetic energy and rotational energy as it rolling downhill

E_p = E_k + E_r

$mgh = 0.5mv^2 + 0.5m\omega^2$

Also velocity of the disk is its angular velocity times its radius:

$gh = 0.5v^2 + \frac{v^2}{2r^2}$

$gh = (\frac{v^2}{2})(1 + \frac{1}{r^2})$

$v^2 = \frac{2gh}{(1 + \frac{1}{r^2}})$

$v = \sqrt{\frac{2gh}{(1 + \frac{1}{r^2})}}$

$v = \sqrt{\frac{1.1g}{(1 + \frac{1}{r^2})}}$

0,0(0 оценок)