2. a weightlifter holds a 150 kg barbell above their head for 10 seconds. the barbell remains stationary…

2. a weightlifter holds a 150 kg barbell above their head for 10 seconds. the barbell remains stationary. how much work did the weightlifter do on the barbell?

2. a weightlifter holds a 150 kg barbell above their head for 10 seconds. the barbell remains stationary. how much work did the weightlifter do on the barbell?

Answer

Explanation:

Step1: Recall work - formula

Work (W = F\times d\times\cos\theta), where (F) is force, (d) is displacement and (\theta) is the angle between force and displacement.

Step2: Analyze the situation

The barbell is stationary, so displacement (d = 0) m. The force (F=mg) ((m = 150) kg, (g = 9.8) m/s²), but since (d = 0), regardless of the value of (F) and (\theta) ((\theta = 0^{\circ}) as the force to hold the barbell is in the direction opposite to gravity), (W=F\times0\times\cos\theta).

Answer:

0 J