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Maximum range at 45°

Intermediate

On level ground the range is greatest at 45°.

Key relationR_max = u²/g

Since sin2θ is largest (1) at θ = 45°, the maximum range is u²/g. With drag or a launch height above the target the best angle becomes smaller than 45°.

Worked example

Throwing at 40 m/s: maximum range ≈ 163 m.

Common mistake

For a launch from a height the optimal angle is less than 45°.

In more detail

With no air resistance, the maximum horizontal range for a given launch speed occurs at a launch angle of 45 degrees, where sin 2θ equals one.

Real-world uses

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Frequently asked questions

Why 45 degrees?

Because sin 2θ is maximum, equal to one, when 2θ is 90 degrees.

Does air resistance change the best angle?

Yes. With drag the best angle is usually a little below 45 degrees.

Does 45 degrees always give the best distance?

On level ground without air resistance, yes. In sport, drag and the launch height above the ground change the best angle.

Related topics in Kinematics

Maximum height · Horizontal range · Complementary angles range · Horizontal projectile · Projectile on an incline · Trajectory equation

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