science
Grade-9
Easy

Question

Peter wants to modify the formula for acceleration
i.e., a = (v – u)/ t
Where v = final velocity, u = initial velocity, t= time, a = acceleration, to suit the special case of freefall of a ball dropped from the top of a building. He chooses to make the following substitutions in the formula.
a. v= 0
b. u= 0
c. a= 9.8 m/s2
Identify the correct substitutions.

  1. Speed = magnitude of velocity
  2. Distance covered = displacement
  3. Acceleration = 0 
  4. All of the above

hintHint:

Speed = magnitude of velocity

The correct answer is: Speed = magnitude of velocity


    In the case of freefall, speed becomes equal to same as the magnitude of velocity as there is no change in direction.

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