During projectile motion (ignoring air resistance), the horizontal component of velocity

Stays constant throughout the flight. The correct answer is stays constant throughout the flight. No horizontal force acts on the projectile, so its horizontal speed never changes. Read more: GenSci0056 — Projectile Motion and Kinematics.

Projectile Motion and Kinematics

A cricket ball thrown into the air. A cannonball fired at an angle. Both trace the same curved shape on their way down.

This curve is a parabola, and the motion behind it is called projectile motion. It builds directly on basic kinematics.

A projectile’s parabolic path, showing launch velocity u, launch angle θ, range x, and maximum height y. Maxmath12, CC0/Public Domain, via Wikimedia Commons.

MCQ Questions

GenSci0056

0° angle

The launch angle that gives a projectile its maximum possible horizontal range, for a fixed launch speed.

Horizontal Motion

Constant speed

No horizontal force acts, so horizontal speed never changes

Vertical Motion

Constant acceleration

Gravity steadily slows the rise, then speeds up the fall

Path Shape

Parabola

Combining both motions traces a curved, symmetric path

Time to Peak

u sinθ / g

Time for vertical speed to drop to zero, at the highest point

The exam angle: the two motions never interfere with each other. Solve the horizontal and vertical parts completely separately, then combine only at the end.

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📑 Contents

1Splitting Motion Into Two Parts
2Key Formulas and Vertical Throws
3Test Yourself
4Range, Maximum Height and Optimal Angle
5Exam Point of View

🏛️ Must Know

Splitting Motion Into Two Parts

Projectile A projectile is any object launched into the air and left to move under gravity alone, ignoring air resistance.
Horizontal Component The horizontal part of the motion has no force acting on it. Horizontal speed stays exactly constant throughout the flight.
Vertical Component The vertical part of the motion is affected by gravity alone. It behaves exactly like an object in free fall.
Independence The two components never affect each other. Solving them separately, then combining the results, is the standard method for every projectile problem.
Parabolic Path Combining constant horizontal speed with steadily changing vertical speed produces a curved, symmetric path called a parabola.

📘 Good to Know

Key Formulas and Vertical Throws

Vertical Throw An object thrown straight up has zero speed at its highest point, for one brief instant, before falling back down.
Time to Reach the Top Time to reach the highest point equals initial vertical speed divided by g, the acceleration due to gravity.
Time of Flight For an object launched and landing at the same height, the total time of flight is exactly double the time taken to reach the peak.
Kinematics Equations The three standard equations of motion, v = u + at, s = ut + ½at², and v² = u² + 2as, apply separately to each component.
Value of g Gravity's acceleration near Earth's surface is taken as 9.8 metres per second squared, often rounded to 10 for quick exam calculations.

Test Yourself

🌟 Great to Know

Range, Maximum Height and Optimal Angle

Range Range is the total horizontal distance a projectile covers before landing back at its starting height.
Maximum Height Maximum height is how far up the projectile rises before its vertical speed drops to zero.
Optimal Launch Angle For a fixed launch speed, a 45° launch angle gives the maximum possible range, ignoring air resistance.
Same Range, Different Angles Two complementary angles, like 30° and 60°, produce exactly the same range, though their maximum heights and flight times differ.
Horizontal Launch An object launched perfectly horizontally, from a height, still hits the ground in the same time as an object simply dropped from that same height, since horizontal speed doesn't affect the fall.

📝 Exam Point of View

NDA & NA (II) 2016 GAT — Vertical Throw Timing

Question NDA & NA (II) 2016, General Ability Test, Q73: a ball is thrown vertically upward at 25.2 m/s. The correct answer for the time to reach its highest point is 2.57 seconds.
Why At the highest point, vertical speed is momentarily zero. Dividing the launch speed, 25.2 m/s, by gravity's pull of 9.8 m/s² gives the time directly.
Link See the full question, NDA & NA (II) 2016 GAT, Q73.

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