On its takeoff roll, the airplane starts from rest and accelerates according to a = a0 − kv2 , where a0 is the constant acceleration resulting from the engine thrust and −kv2 is the acceleration due to aerodynamic drag. If a0 = 2 m/s2 , k = 0.00004 m−1, and v is in meters per second, determine the design length of runway required for the airplane to reach the takeoff speed of 250 km /h if the drag term is (a) excluded and (b) included.

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A250-n box is at rest on a frictionless horizotal floor. then a person shoves the box with a non-zero force of magnitude p. which statement best describes the relationship betweeen p and the motion of the box after it was shoved? -the box will not move when p< 250n but otherwise will accelerate at a constant rate that is directly proportional to p - the box will begin moving at a speed that is directly proportional to p, then will gradually slow to a halt -the box will move with constant velocity at a speed that is directly proportional to p -box will accelerate across the floor at a constant rate that is directly proportional to p

What is a subatomic particle with a negative charge and very little mass?