Question

question 17 1 pts nellie tosses a ball upward at an angle. neglecting air resistance, the vertical component of the initial velocity remains constant. increases with time to reach the top. decreases with time to reach the top. question 18 1 pts the lift experienced by a helicopter involves an action - reaction pair of forces between the motion of the helicopter relative to the ground below. mass of the helicopter and earths mass. helicopter blades and the air. weight of the helicopter and atmospheric pressure. any or all of the above

Explanation:

For Question 17: When a ball is tossed upward at an angle and air - resistance is neglected, the vertical component of the initial velocity is affected by the gravitational force acting downward. This causes the vertical velocity to decrease until it reaches zero at the top - most point of the ball's trajectory.
For Question 18: According to Newton's third law, the lift experienced by a helicopter is due to the action - reaction pair of forces between the helicopter blades and the air. The blades push the air downward (action force), and in return, the air pushes the blades (and thus the helicopter) upward (reaction force).

Answer:

Question 17: decreases with time to reach the top.
Question 18: helicopter blades and the air.