posted by Ari .
A car starts from rest and travels for 7.8 s with a uniform acceleration of 3.2 m/s2. The driver then applies the brakes, causing a uniform acceleration of −1.1 m/s2. If the brakes are applied for 2.8 s, how fast is the car going at the end of the braking period? Answer in units of m/s.
3.2*7.8 - 1.1*2.8 = ___?