Which one is the dimensionally correct equation ?
Correct answer: B. S=Vit+1/2at2
- A. f=vt
- B. S=Vit+1/2at2
- C. V=St
- D. V=f/t
Explanation
In S = Vit + 1/2at², Vit has dimensions (m s-1)(s) = m and at² has dimensions (m s-2)(s²) = m, so every term has the dimension of displacement. The other equations do not match dimensions, such as f = vt, whose right side has dimensions of length. Students may choose D by confusing the relationships among speed, frequency, and time.
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About Displacement and Velocity
Displacement is the directed change in position, while velocity is the rate of change of displacement and includes both magnitude and direction. The topic connects position-time and velocity-time graphs with average and instantaneous values, and distinguishes displacement from distance and velocity from speed.
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