physics
posted by alex .
Initially (at time t = 0) a particle is moving vertically at 5.8 m/s and horizontally at 0 m/s. Its horizontal acceleration is 2.1 m/s^2. At what time will the particle be traveling at 54◦ with respect to the horizontal? The acceleration due to gravity is 9.8 m/s^2

tan54 = Y/X,
tan54 = 5.8 / X,
X = 5.8 / tan54 = 4.21m/s.
t = (Vf  Vo) / a,
t = (4.21  0) / 2.1 = 2.0s.