posted by Jim .
a sled is capable of reaching speeds of 450 m/s in 1.82 s then stopped in 1.92 s what is the acceleration
The acceleration rate is 450/1.82 = 247 m/s^2 (or 25.2 g's)
The deceleration rate is 450/1.92 = 234 m/s^2. That can be considered negative acceleration