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Two friends, Joe and Sam, go to the gym together to strength train. They decide to start off with an exercise called flat bench press. Lying flat on a bench with their arms in an extended position, they slowly lower (to their chest) and then raise a barbell back to the starting position. They start off by using a 31.5 kg barbell. Joe is taller than Sam which means Joe's arms are 68.6 cm long while Sam's are 60.8 cm. Calculate the work done by Joe, W_joe, when he raises the barbell to finish one repetition. The acceleration due to gravity is 9.81 m/s^2.
Remember does the exercise. How does the amount of work Sam does, W_sam, lifting the weight the correct operator from the list below.
W_sam = W_Joe
W_sam > W_Joe
Wsam < W_Joe

Respuesta :

gilcarusolautaro

Answer:

The work done by Joe, W_joe, when he raises the barbell to finish one repetition is 211.98J

The correct option is Wsam <W_Joe.

Explanation:

From the mass of the bar, the acceleration of gravity and the distance that the bar travels in each of them when performing the lifting movement from the chest you can calculate the work done by each one:

W_joe= 31.5kg × 9.81 (m/s^{2} ) × 0.686m = 211.98J

W_sam= 31.5kg × 9.81 (m/s^{2} ) × 0.608m = 187.88J

187.88J < 211.98J ⇒  Wsam <W_Joe

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