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| Projectiles |
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| So far we have studied only the motion of an object under only one force. In this section we are going to study the motion of an object acted upon by two forces acting at right angles to each other. When an object is thrown horizontally from a certain height from the ground, then the object follows a curved path. An object thrown into space horizontally under the action of Earth's gravity is called a “Projectile”. |
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| Trajectory of a stone thrown horizontally |
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| Examples: |
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 A Bullet fired from a gun. |
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A bomb released from a moving aircraft. |
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A ball released horizontally in air. |
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| In all the above mentioned examples the object follows a curved path. |
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| The path followed by a projectile is called its “Trajectory”. |
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| The horizontal distance covered by a projectile is called its “Range” and the time taken by the projectile from the moment it is projected, till it touches the ground is called the “Time of Flight of the Projectile”. |
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| The trajectory, range and time of flight are known as the parameters of a projectile. |
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| Parameters of a projectile |
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| Now, let us see why projectiles follow a curved path. A projectile is acted upon by two forces namely, |
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the horizontal force with which the projectile is thrown |
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the vertically downward force due to the force of gravitation |
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| The projectile moves forward due to the horizontal force and downwards due to the force of gravity. The projectile follows a curved path since both the forces act simultaneously on it. Thus a projectile possesses a horizontal motion with a constant velocity and a vertical motion downwards with a constant acceleration. |
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