Spacecraft mass	2500	kg
Velocity of projectile	4000	m/s
Projectile weight	10	grams
or	0.01	kg
Spacecraft aceleration	8	G
or	78.48	m/s2
Delta-V	0.016	m/s
Time between impacts	0.000204	s
Frequency	4905	Hz
Distance between projectiles	0.815494	m
That mean	2452.5	Projectiles per 2 km
Delta-V requirements	7.9	km/sec
or	7900	m/sec
You will need	493750	projectiles
or	201.3252	packages
With total weight	4937.5	kg
	0.663866
	0.032426
	77099.57
To achieve the same velocity, classical rocket will require	77.10	tones of fuel