The motion of a particle along a straight line is described by equation: x = 8 + 12t - t3 where x is in metre and t in second. The retardation of the particle when its velocity becomes zero is

  1. 12 ms-2
  2. 24 ms-2
  3. zero
  4. 6 ms-2

Answer (Detailed Solution Below)

Option 1 : 12 ms-2
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Detailed Solution

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CONCEPT

ACCELERATION & DECELEARATION:

  • Acceleration is the measure of the rate of change of velocity with respect to time, the value of acceleration can be both positive and negative.  

​                                                                                                                                                                                                                   Where v= Final velocity, u =Initial velocity and t = time 

  •  Deceleration is the negative rate of change of velocity.        

CALCULATION:

Given - x = 8 + 12t - t3

  • As we know, velocity is defined as the rate of change of displacement.

   

When V = 0, then

⇒ 12 - 3t2 = 0

⇒ 12 = 3t2

⇒ t = 2 sec

  • The retardation is given by

 

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