Answer : The momentum of a dog is, 112 kg.m/s
Explanation :
Momentum : It is defined as the motion of a moving body. Or it is defined as the product of mass of velocity of an object.
Formula of momentum is:

where,
p = momentum
m = mass = 14 kg
v = velocity = 8 m/s

Therefore, the momentum of a dog is, 112 kg.m/s