3.4 Projectile Motion

• Projectile Motion - motion of an object thrown or projected into the air, subject to only the acceleration of gravity
• The object is called a projectile, and its path is called a trajectory
• The motion of falling objects is a one-dimensional type of projectile motion with no horizontal movement
• Projectile Motion has no air resistance
• that motions along perpendicular axes are independent and thus can be analyzed separately.
• The key to analyzing two-dimensional projectile motion is to break it into two motions, one along the horizontal axis and the other along the vertical.
• • to describe motion we must deal with velocity and acceleration, as well as with displacement, and find their components along the xand y-axes
• h = initial velocity y-axis^2/2(gravity)
• vertical and horizontal motions are independent of each other in projectile motion(Gallileo found this first, used to find range)
• Range - horizontal distance R traveled by a projectile
• the greater the initial speed v0, the greater the range
• initial angle 0o has a dramatic effect on the range,
• Range of a projectile on level ground where air resistance is negligible: R = initial velocity^2 sin 2(initial angle) / gravity
• R is very small compared to the circumference of the earth when talking about the range of a projectile on ground level. The range is large, the Earth curves away below the projectile, and acceleration of gravity changes direction along the path
• If initial speed is great enough, the projectile goes into orbit.
• When an object is in orbit, the Earth curves away from underneath the object at the same rate as it falls. The object thus falls continuously but never hits the surface