Answer:
0.0005217 m/s or 5.217×10⁻⁴ m/s
Explanation:
Speed: This can be defined as the ratio of the distance covered by a body to the time taken to cover that distance. The S.I unit of speed is m/s. Speed is a scalar quantity, because it can only be represented by magnitude only.
Mathematically, speed is expressed as
S = d/t ......................................................... Equation 1
Where S = speed, d = total distance, t = time taken to cover the distance
Given: d = 120 mm = (120/1000) m = 0.12 m, t = 230 s.
Substituting into equation 1
S = 0.12/230
S = 0.0005217 m/s
Hence the speed of the security guard = 0.0005217 m/s or 5.217×10⁻⁴ m/s
