# Projectile motion without air resistance [closed]

Does the mass of projectile affect its trajectory when it is projected in no air resistance environment and why?

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check here for more explanation physicstutorials.org/home/mechanics/1d-kinematics/… –  Smith Apr 9 '11 at 16:42

## closed as off-topic by tpg2114, Qmechanic♦Nov 3 '13 at 2:29

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No, the mass affects nothing; only the initial velocity, angle of projection and acceleration due to gravity determine the trajectory the projectile takes.

This is because the inertial mass $m_i$ which appears in $F=m_ia$ is equal to the gravitational mass $m_g$ which appears in $F=m_gGM/R^2$ of Newton's gravitational law. These two cancel in all your equations. This property of masses is one way of stating Einstein's Equivalence Principle.

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I see, so more force will be required to attain the same velocity. –  user2363 Mar 2 '11 at 23:00
For example, Earth's mass is $6 \times 10^{24}$ kg, so even a large aircraft or spacecraft of $10^6$ or $10^7$ kg will not have a measurably different trajectory because of its mass. However, the Moon is $7 \times 10^{22}$ kg, so its trajectory is measurably different from what it would be if it were massless.