A projectile is traveling in a parabolic path for a total of 6 seconds. it's initial horizontal speed is 10 meters per second. at 6 seconds it strikes the ground. a) what is the acceleration of the projectile at the 3 second mark where it is at the top of it's trajectory? b) what is the total velocity of the projectile at the 3 second mark where it is at the top of it's trajectory? c) what is the velocity in the x-direction of the projectile at the 3 second mark where it is at the top of it's trajectory? d) what is the velocity in the y-direction of the projectile at the 3 second mark where it is at the top of it's trajectory?