An object is thrown horizontally with a velocity of 30 m/s from the top of a tower. It undergoes a constant downward acceleration of 10 m/s2. The magnitude of its instantaneous velocity after 4.0 sec, in meters per second, is:
To approach this question I first thought to myself that the velocity in the y-component after 4s is going to equal 10+2(10)+3(10)+4(10); 100m/s. The x velocity will remain constant. Thus the velocity at t=4 would be the resultant vector of 100m/s in the y and 30m/s in the x, which equals 104.4m/s. I am wondering where I am going wrong with my reasoning here?