- #1

nukeman

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**Weight lifter - Acceleration of the barbell ??**

## Homework Statement

Here is the info, and below are the questions I am a little stuck on...

"An athlese who mass is 90.0 kg is performing a lift exercise. Starting from the rest position, he vertically lifts a barbell weight that weighs 490N (50kg). He lifts the barbell a distance of 0.60 m in 1.6 seconds. Assume that the barbell has a constant upward acceleration and the athlete has no accerlation as he lifts the weight.

1) How would I draw a FBD for the barbell and the athlete? Which forces are acting on each the barbell and athlete?

2) Find the force that the athlete applies to the barbell to accerlate it?

3) Find the total force that the athlete's feet exert on the ground as he lifts the barbell?

## Homework Equations

## The Attempt at a Solution

1) How would I draw a FBD for the barbell and the athlete? Which forces are acting on each the barbell and athlete?

*For the FBD on the barbell - Would it just be gravity(Fg) and applied(Fa) force pulling the weight up?*

Not sure how to make a FBD for the athlete?

Not sure how to make a FBD for the athlete?

2) Find the force that the athlete applies to the barbell to accerlate it?

*Would it just be applied force?*

3) Find the total force that the athlete's feet exert on the ground as he lifts the barbell?

*Really stuck on this one!*