Amissile is fired from a jet flying horizontally at mach 1 (1100 ft/s). the missile has a horizontal acceleration of 1000 ft/s 2 . calculate its horizontal velocity at 10.0 seconds after it is fired. (assume constant acceleration of the missile throughout its flight.)

Vo = 1100 ft/s 
a = 1000 ft/s^2 
t = 10 s 
Use velocity formula 
Vh = Vo + at 
Vh = 1100 ft/s + 1000 ft/s^2 *10 s 
Vh = 11,100 ft/s 

Explanation: In this case, the missile continues travelling at the plane's initial velocity, Vo, (due to Newton's 1st law) with an added velocity component, V = a*t, due to the missile's acceleration. The two velocity components are vectors which act in the same direction, so they may be summed together. 

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V = u + a*t = 1100ft/s + (1000*10) ft/s = 11100 ft/s 
Answer is 11,100 ft/s