Question

An object starts moving from the rest with uniform acceleration 4m/s2 . find velocity of body after 4s

Answer 1

Answer:

After 4 seconds the velocity of body will be 16 m/s

Answer 2

αηѕωєя

• In order to answer this question, we must apply newton's first equation of motion

v = u + at

• Where v is the final velocity in m/s, which is we shall attempt to find,

• u is the initial velocity in m/s, given in the question as 20m/s

• a is the acceleration of the body in m/s2, in the question, it is indicated to be 4m/s2

• t is the time in seconds, from the question, it is 4s.

• $v = 20 + 4 \times 4 \\ </li></ul><p></p><ul><li>v = 20 + 16 = 36m/s</li></ul><p>$
  • As for the distance, either the second or third equation of motion can be used.

  Using the second equation,

  $</p><ul><li>s (distance) = u \times t + 0.5 \times a \times (t^2) \\ </li></ul><p></p><ul><li>s = 20 \times 4 + 0.5 \times 4(4 \times 4) \\ </li></ul><p></p><ul><li>s = 80 + 32 = 112m</li></ul><p>$

  Using the third equation of motion,

  $v2 = u2 + 2as \\ </p><ul><li></li><li>36^2 = 20^2 + 2 \times 4 \times s \\ </li></ul><p></p><ul><li>1296 = 400 + 8 \times s \\ </li></ul><p></p><ul><li>8 \div s = 1296 - 400 = 896 \\ </li></ul><p></p><ul><li>s = 896/8 = 112m$

$hope \: its \: help \: u$