A pole-vaulter just clears the bar at 5.31 m and falls back to the ground. The change in the vaulter's potential energy during the fall is -3900 J. What is his weight?

Weight = 734.46 N

Explanation:

Given:

Initial height of the pole-vaulter is,

Final height of the pole-vaulter is,

Change in the vaulter's potential energy is,

We know that, change in potential energy is given as:

Where, 'm' is the mass of the object, 'g' is acceleration due to gravity and has a value of 9.8 m/s².

Now, weight of the object is given as the product of its mass and acceleration due to gravity. So, replace 'mg' by weight 'w'. So, the equation becomes,

Now, rewriting in terms of 'w', we get:

Now, plug in all the given values and solve for 'w'. This gives,

Therefore, weight of the vaulter is 734.46 N.

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