2Fact or FictionFor a fastball to travel at 90 mph, the pitcher’s hand (or fingers) must be moving at 90 mph when the ball is releasedThe moon is constantly falling towards EarthA coin dropped off a cliff will reach the ground before another coin thrown horizontally from the cliff at the same height.
3ProjectileObject that is launched by a force and continues to move by its own inertiaOnly force acting on object is gravityTrajectory- the path of a projectile (parabola)
5Projectile MotionHorizontal (x) and Vertical (y) components are independent of each otherNo force acts horizontally; Horizontal motion is constant.Force of gravity acts vertically; vertical motion is accelerated
6What does this mean?Objects propelled horizontally also fall vertically at a rate of +9.8 m/s2 (No matter how hard object is thrown)Horizontally launched object and one that is dropped
14Projectiles have 2 velocities- Horizontal and Vertical! Force of gravity only acts verticallyVertical Velocity (Vy) - Force of gravity accelerates objects vertically at a rate of 10 m/s2 downward. (So in the vertical direction the ball slows down on the way up and speeds back up on the way down by 10 m/s every second)Horizontal Velocity (Vx)In absence of air resistance, projectile maintains initial horizontal velocity it was given. (Inertia) Vx is constant!Vix = Vx = constantVx = dx/t
15Objects that are thrown horizontally only one factor determines the time in air. Object's initial height (dy)t in air =dy
16Objects that are thrown horizontally To find the maximum range (dx) or horizontal displacement use the formula:dx = vxt
17Ex. A stone is thrown horizontally at 7. 5 m/s from a cliff that is 68 Ex. A stone is thrown horizontally at 7.5 m/s from a cliff that is 68.4 m high. How far from the base of the cliff does the stone land?Draw a diagram of this situationBreak up information into x and y!27.8 m from the base of the cliff
18Ex. A baseball is thrown horizontally with a velocity of 44 m/s Ex. A baseball is thrown horizontally with a velocity of 44 m/s. It travels a horizontal distance of 18 m to the plate before it is caught.A. How long does the ball stay in the air?B. How far does the ball drop during its flight?A = 0.41 s B = 0.82 m
19What will happen if a pilot drops a package when the plane is directly over the target?
20The trajectory of a projectile launched upwards looks like...
21Monkey and the tranquilizer gun A scientist needs to shoot the monkey with a tranquilizer gun, but he knows that as soon as he shoots the gun, the monkey will let go of the tree and fall to the ground. Should he aim (above, beneath, or straight at) the monkey?Monkey & the Hunter
26Satellites are Projectiles that fall around Earth The moon is a satelliteGeosynchronous orbits match the Earth’s spin
27Show what you know 1. A projectile’s motion is... a. linear.b. one-dimensional.c. two-dimensional.d. three-dimensional.2. A projectile’s horizontal motion is...a. uniform (constant).b. accelerated.c. absent.
28Show what you know3. The vertical component of a projectile’s motion is...a. uniform (constant).b. accelerated.c. absent.4. A boy is riding a skateboard along a smooth, flat street. If he jumps straight up off the board, he will land...a. in front of the board.b. behind the board.c. on the board.