NABIL ALI PATRICK CLEWELL VLAD SOLOMON PROJECTILE MOTION NABIL ALI PATRICK CLEWELL VLAD SOLOMON

What is a Projectile? A projectile is any object that moves through the air or through space, acted on only by gravity (and air resistance, if any) Gravity causes launched projectiles to move in a curved path and then hits the ground, without gravity the projectile would move in a straight path. Without air resistance the time it takes a launched projectile to go up would equal the time it takes to come down.

Information When an object is thrown at an angle up into the air, ignoring air resistance, the acceleration of the object is -10 m/s squared. (Negative is downward) The graph of an object’s trajectory is usually a downwards parabola. Ignoring air resistance, the horizontal component of the projectile’s velocity is constant. Vertical velocity at the peak of a projectiles flight is always zero.

Additional Information - The horizontal component of motion for a projectile is just like the horizontal motion of a ball rolling freely along a level surface (without the effects of friction, the ball moves at a constant velocity and covers equal distances in equal time intervals) - Because gravity acts downwards, and there is no horizontal force (such as someone pushing the object), then there is no horizontal acceleration

Additional Information - Vertical component of a projectile’s velocity is similar to free falling objects in that the distance covered increases over an equal time interval until terminal velocity is reached at the ball no longer accelerates - It is important to remember that the horizontal component of motion remains independent of the vertical component of the motion (this means that as the vertical distance increases over an interval of time, the horizontal distance stays the same)

Effects of Air Resistance - As an object moves through the air, there are resistances that effect the speed, distance and height (Ex. A coin falls much faster then a feather, not only because the feather is lighter, but also because the air resists it better) The speed of descent is a function of air resistance rather than mass (take two identical pieces of paper- wad up one and leave the other untouched and see which one lands first) Air resistance causes drag- a force that opposes the forward motion of the object

Quick Quiz 1. Which of the following is NOT an example of projectile motion? A. A baseball hit by a bat B. An Airplane flying flat and level C. A cannonball shot off a cliff D. A volleyball served over a net

Quick Quiz Answer The correct answer is B. An airplane flying flat and level. All the other choices are examples of projectile motion because they are being acted upon by the earth. (Once they leave your arm/cannon, air resistance and gravity affect its trajectory and brings them down). An airplane is constantly flying with its engines keeping it from falling down.

Factors Which Influence Projectile Motion The speed at which it is launched. The angle at which it was launched. The height from which it was launched. These three factors (speed, angle, and height) help to determine how fast, how high, how long, and how far a projectile will travel.

Real Life Applications -”Ballistics”- Law-enforcement investigators determine when, where, and how a firearm was used (changing shapes of bullets and adding more force to the gun when it fires allows for bullets to be fired farther and more accurately due to a lowered air resistance) - Led to advancement of weaponry (lead balls and muskets were highly inaccurate because balls were not fitted to the gun barrel, and thus, balls bounced off sides of barrel and trajectory was unpredictable)

Satellites Definition: a projectile travelling fast enough to fall around the earth rather than into it -While there may be no air resistance in outer space, gravity still effects the object and keeps it rotating around the Earth - A satellite is continually falling around the Earth -When gravity is the only force acting on a projectile near the Earth, the horizontal component of its velocity does not change

Projectile Motion

Projectile Motion

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