A boy weighing 25 kgf climbs up from the first floor al a height of 3 m above the ground to the thind floor al a height of 9 m above the ground. What will be the increase in his gravitational potential energy? (Take g = 10 N `kg^(-1)`)

Explanation

To find the increase in gravitational potential energy (ΔPE) when a boy weighing 25 kgf climbs from a height of 3 m to a height of 9 m, we can follow these steps:

### Step 1: Convert the weight from kgf to Newtons
The weight of the boy is given as 25 kgf. To convert this to Newtons, we use the relation:
\[ \text{Weight (W)} = \text{mass (m)} \times g \]
Given that \( g = 10 \, \text{N/kg} \):
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