Abullet traveling at 5.0 x 10^2 meters per second is brought to rest by a 50 newton * second impulse. what is the mass of the bullet?

As an equation this is: 
(F)(delta t) = (m)(delta v). 

You are given the impulse 
(F)(delta t) = 50 Ns 
You are given that the bullet goes from 500 m/s to 0 m/s, so delta v is 500 m/s. 

All you need to do is set up the equation: 
50 Ns = 500(m) m/s. 

Looks a lot like m = 0.1 kg

Answer the above statement is ( false );

Since the pully is a simple machine so the mechanical advantage is a 1