Question

A weightlifter takes 0.5s to raise a barbell with 2 free-weights from the ground to a height of 0.9m. If each free-weight has a mass of 30kg and the barbell has a mass of 20kg, calculate how much power the weightlifter produces when lifting the barbell?​

Answer 1

Answer:

P = 1412.82 [Watt]

Explanation:

First we must calculate the total mass that makes up the barbell and the two free weights at each end of the barbell.

$m=30+30+20\\m= 80 [kg]$

Weight is now defined as the product of mass by gravitational acceleration.

$w=m*g$

where:

m = mass = 80 [kg]

g = gravity acceleration = 9.81 [m/s²]

$w=80*9.81\\w=784.8[N]$

Now using the product of the weight by the distance traveled we can calculate the work.

$W=w*d$

where:

W = work [J]

w = weight = 784.8 [N]

d = distance = 0.9 [m]

$W=784.8*0.9\\W=706.41[J]$

And power is defined as the relationship of work at a certain time. The potency is expressed by means of the following formula.

$P=W/t\\P=706.41/0.5\\P=1412.82[W]$