Chapter 10: Projectile and Satellite Motion (from Lecture Slide) Flashcards
Projectile
Any object that moves through the air or space under the influence of gravity, continuing in motion by its own inertia
Trajectory
The path of the projectile
Projectile motion are three examples of
1) An object thrown vertically upward
2) An object thrown upward at an angle to be horizontal
3) An object dropped from rest
Without gravity, a tossed object follows a
Straight line path
With gravity, the same object tossed at an angle follows a
Curved path
Projectile motion is a combination of
A horizontal component and a vertical component
Acceleration due to gravity only affects the
Y-axis motion (vertical velocity)
Projectile motion: Horizontal component
No horizontal force component equal to constant velocity
Projectile travels equal horizontal distances in
Equal time periods
Projectile motion: Vertical component
Affected by the acceleration due to gravity
Gravitational force is downward so projectiles accelerates
Downward
Slow down on the way and speeds up on the way
Down
Combining the horizontal and vertical components produces a
“Curved path” referred to as a parabola
Parabola
Curved path of a projectile that undergoes acceleration only in the vertical direction, while moving horizontally at a constant speed
- Consider a cannonball launched horizontally, gravity causes the cannonball to accelerate downward at a rate of 9.8 m/s^2
1) Y-component of velocity only points downward (only falls)
2) X-component of velocity remains constant
- Consider a cannonball launched upward at an angle to the horizontal
1) Horizontal velocity component same as before, remains constant
2) Vertical velocity component is different, the cannonball now rises before falling
The velocity of a typical projectile can be represented by horizontal and vertical components. Assuming negligible air resistance, the horizontal component along the path of the projectile
Remain the same
When no air resistance acts on a fast moving baseball moving in a parabolic path, its acceleration is
Downward
As the projectile rises toward its max height, it is
Slowing down
As it falls from its max height, the magnitude of the vertical velocity is
Increasing
The vertical velocity one second before reaching its peak is the same as
The vertical velocity one second after falling from its max height
Although different directions, magnitudes are
Equal
Assuming negligible air resistance, the vertical component along the path of the projectile
Changes throughout
Launch angle determines the range and maximum height that an object will
Experience after being launched
The same object being launched at the same speed but different
Angle
Maximum height occurs for a launch at
90 degrees
Maximum range occurs for launch at
45 degrees
Same range obtained from
Complementary angles
A projectile is launched at an angle into the air. Neglecting air resistance, what is its vertical acceleration? Its horizontal acceleration?
g in the vertical, zero acceleration in the horizontal
Without air resistance, the time for a projectile to reach maximum height is
Halfway between when it was launched and when it descends to its initial height
In the presence of air resistance, the path of a high-speed projectile falls
Below the idealized parabola
With no air resistance: time up equal to
Times down
With no air resistance: 45 degrees gives
Max range
With air resistance: Time up is less than
Times down
With air resistance: Max range occurs at
Less from 25 degrees to 34 degrees
Downward resistance forces are greater on the way up than the way
Down, the net effect is to spend less than in the air
Satellite
A projectile that falls around Earth rather than onto it