Home › AP Physics 1 › Physics › Two-Dimensional Kinematics and Projectile Motion › A projectile's horizontal velocity stays constan…
A projectile's horizontal velocity stays constant during flight because:
AGravity acts horizontally
BAir resistance cancels it
CThe projectile is spinning
DGravity has no horizontal part
Answer & Solution
Correct answer: D. Gravity has no horizontal part
1. Only a force in a direction can change the velocity in that direction.
2. Because gravity is vertical, its horizontal component is zero.
3. With no horizontal acceleration, the horizontal velocity cannot change.
4. The vertical velocity meanwhile changes steadily under gravity.
5. That contrast between the two components is what curves the trajectory.
_Source: OpenStax College Physics for AP(R) Courses 2e (CC BY 4.0), Ch 3 'Two-Dimensional Kinematics', sections 3.1-3.4_
Related questions
Choosing which direction counts as positive in a projectile problem affects:The head-to-tail method gives the same resultant regardless of the order the vectors are dResolving projectile motion into perpendicular directions works because each direction canThe independence of horizontal and vertical motion means a ball dropped and a ball fired hThe two named approaches to vector addition and subtraction are graphical methods and:Subtracting vectors is described as analogous to the subtraction of:If you set up a coordinate system with downwards as positive, the acceleration due to gravBecause gravity acts vertically, the horizontal acceleration of a projectile is: