Let the total weight of the 5 friends be \( 5 \times 52 = 260 \) kg.
When the new friend joins the group, the average weight increases by 1.5 kg, making the new average weight:
\[
52 + 1.5 = 53.5 \, \text{kg}
\]
Thus, the total weight of the 6 friends is:
\[
6 \times 53.5 = 321 \, \text{kg}
\]
The weight of the new friend is the difference between the total weight of the 6 friends and the total weight of the 5 friends:
\[
321 - 260 = 61 \, \text{kg}
\]