Term
| T or F. When a projectile is fired at an angle from the ground (neglecting air resistance) the horizontal and vertical velocity components are both zero at the highest point in its flight. |
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Definition
| False. At the highest point in the projectile flight, only the vertical velocity reaches zero. Horizontal velocity is not zero as long as the projectile is fired at some angle other than 90 degrees. |
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Term
| A projectile is fired from ground level at an angle, with an initial vertical speed of 30 m/s and initial horizontal speed of 15 m/s. Assuming the ground is level, air resistance is negligible, and g = 10 m/s^2, the distance horizontally that the object will strike from the initial point is ____________. |
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Definition
90 m.
Vertical time to top is 3 seconds
Total time in the air is 6 seconds
Horizontal distance: d = vt
d = 15 m/s x 6 seconds = 90 m. |
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Term
| For a freely falling object in projectile motion, what is the acceleration in the x-direction? |
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Definition
| Zero. Gravitational acceleration has only a downward, constant y-axis component with a magnitude of g. |
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Term
| What is the acceleration in the y-direction for a freely falling body in projectile motion? |
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Definition
| The acceleration is a = -g, where g is 9.81 m/s^2. The equations of motion are the same as for other systems of constant acceleration. |
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