Kinematics

A particle has an initial velocity of 3i + 4j and an acceleration of 0.4i + 0.3j. Its speed after 10s is

  1. 7(√2) units
  2. 10 units
  3. 7 units
  4. 8.5 units

Solution

Use equation of kinematics: v = u + at

Initial Velocity, u = 3i + 4j

Acceleration, a = 0.4i + 0.3j

Time, t = 10s

v = (3i + 4j) + 10(0.4i + 0.3j)

v = (3i + 4j) + (4i + 3j)

v = 7i + 7j

|v| = √(72+72) = 7(√2)

Correct option is A.