99 Percentile Qs Bank for JEE MainPhysicsMotion in One Dimension
A particle moving in a straight line covers half the distance with a speed of 3   m s - 1 . The other half of the distance is covered in two equal time intervals with speeds of 4.5   m s - 1 and 7 . 5   m s - 1 . The average speed of the particle during this motion is
Options
- A4   m s - 1
- B5   m s - 1
- C  5 . 5   m s - 1
- D  4 . 8   m s - 1
Correct answer
A. 4   m s - 1
Step-by-step solution
Let total distance be S and time required to cover first half is t 1 and second half is 2 t 2 . Since Time= Distance Speed Given, t 1 = S 2 3 = S 6 ,   t 2 = S 1 4 . 5 = S 2 7 . 5 From the given data, we know that S 1 + S 2 = S 2   ⇒ 4 . 5 t 2 + 7 . 5 t 2 = S 2     ⇒ t 2 = S 24 Average speed = S t 1 + 2 t 2 = = S S 6 + 2 S 24 = 4   m   s - 1