A projectile follows a straight-line path instead of a parabolic trajectory. Which could be the launch angle? would it be 90 or 45 or 3o??

Answer:90 degreeExplanation:For the horizontal projection or the vertical projection, the path traversed by the projectile is a straight line .So the angle of projection is 0 degree or 90 degree. In this condition the motion is in one dimension. If the angle of projection is any arbitrary angle except 0 degree or 90 degree, the motion of the projectile is parabolic.

projectile can only follow the straight line path when it is launched upward straightly so the correct option is 90 degree with respect to horizontal x -axis ..:)