A 42 kg object goes from rest to 23 m/s, calculate the magnitude of the impulse

Impulse is obtained by multiplying force by time.

From your previous post, we have obtained the force which is

F = 1441.8 N. I believe that the two questions are related, so let us use the value of time stated there, which was t = 0.67s.

Using the formula:

I = F x t

I = 1441.8N x 0.67s

I = 966 Ns

Impulse = mass * velocity

impulse = 42 * 23 = 966 N. s