People with slow swings should buy lighter racquets to have more power?
I have a pretty slow swing it seems and i had trouble hitting deep shots with my older racquet.
Yeah. Lighter frames generate more power, or, in a point of view of Physics, they absorb less the energy of the impact. That makes the ball "rebound" from the racket faster, but the lighter frame, as it's unable to absorb the energy, makes your arm take the impact, generating injuries.
The fact is that "lighter" frames have the weight dislocated to the racket head, and that's what generates more power. Balanced and "head light" (weight in the handle) rackets feel more natural and protect your arm. I wouldn't recommend using a very light racket. Unless you hardly play.