A particle A A\,A moves with constant acceleration (−2i+4j) ms−2(-2\mathbf{i} + 4\mathbf{j}) \text{ ms}^{-2}(−2i+4j) ms−2. At time t=0t = 0t=0, A A\,A has speed u ms−1u \text{ ms}^{-1}u ms−1. At time t=5 st = 5 \text{ s}t=5 s, A A\,A has velocity (−5i+8j) ms−1(-5\mathbf{i} + 8\mathbf{j}) \text{ ms}^{-1}(−5i+8j) ms−1.
Find the value of uuu.