Question

a rowboat passenger uses an oar to push the boat off the dock by exerting a force of 60.0 N for 2.0 s. what impulse acts on the boat?

Answer 1

By definition, the impulse is given by the product of the average force multiplied by the time interval in which this force is applied.
 In other words, the impulse is:
 I = F * delta t
 Substituting the values:
 I = (60.0) * (2.0)
 I = 120.0 N * s
 Answer:
 impulse acts on the boat is I = 120.0 N * s

Answer 2

Impulse is the change of momentum of an object when the object is acted upon by a force for an interval of time. It is simply calculated by the expression:

Impulse = F(change in time)
Impulse = 60(2)
Impulse = 120 Ns