Step-by-step explanation:
Given that,
Mass of a puck, m = 8 kg
Initial velocity, u = 10i m/s
Final velocity, v = (10i+12j) m/s
Time, t = 8 s
(a) Force acting on an object is given by the product of mass and acceleration.
F = ma
a is acceleration

(b) The magnitude of force is given by :

Hence, the component of force is 12j N and its magnitude is 12 N.