NEET2018PhysicsMotion in One DimensionActual
A toy car with charge q moves on a frictionless horizontal plane surface under the influence of a uniform electric field E → . Due to the force   q E → , its velocity increases from 0 to 6   m   s - 1 in one second duration. At that instant the direction of the field is reversed. The car continues to move for two more seconds under the influence of this field. The average velocity and the a
Options
- A1   m   s - 1 ,   3.5   m   s - 1
- B1   m   s - 1 ,   3   m   s - 1
- C2   m   s - 1 ,   4   m   s - 1
- D1.5   m   s - 1 ,   3   m   s - 1
Correct answer
B. 1   m   s - 1 ,   3   m   s - 1
Step-by-step solution
0 < t ≤ 1 s velocity increases from 0 to 6 m/s 1 s ≤ t ≤ 2 s : velocity decreases from 6 m/s to 0 m/s But car continues to move forward and then it reverses its direction at t = 2  s and after 2 s accelerates backward Distance undefined | 1 2 × 6 × 2 | + | 1 2 × ( − 6 ) × 1 | = 6 + 3 = 9  m Displacement = Total area under v − t graph = 6 − 3 = 3 m ∴ Average velocity = Displacement Time = 3 3 = 1 m/s ∴ Average speed