Velocity
What is the vertical velocity at the peak of a projectile's trajectory?
zero
What is the equation for horizontal velocity of a projectile? (not at an angle)
vxi = vxf
The main factor affecting vertical velocity is ___________.
Gravity
Why do we use separate equations for vertical and horizontal motion of a projectile?
Because the motion is completely independent- vertical velocity is completely unaffected by horizontal velocity and vice versa
What is the main rule of vector addition?
Add vectors tip to tail
If a ball is thrown straight up with a velocity of 5.8 m/s, what will its velocity be as it approaches the ground (on the opposite side of the parabola)?
What is 5.8 m/s
The horizontal velocity is UNaffected by what?
gravity
What is the definition of a projectile?
An object that is thrown, kicked, batted, or otherwise launched into motion and then allowed to follow a path determined solely by the influence of gravity.
At what part of the projectile will the object have minimum speed?
The top of the peak.
If the vertical component of a vector is 3 meters and the horizontal component is 4 meters, what is the length of the resultant?
5 meters
What is the magnitude of velocity called?
speed
How does horizontal velocity change throughout an object's projectile?
It doesn't- horizontal velocity is constant in projectile motion
What is the only thing a projectile's time of flight depends on?
Vertical velocity
In what direction is all of the velocity at the top of a projectile's peak?
Horizontal
Find the length of the resultant: it is at an angle of 25 degrees above the x-axis and has a horizontal component of 30 meters
33 meters
What factor does vertical velocity depend on?
Gravity
What is the position-time equation for horizontal motion of a projectile with an initial velocity at an angle?
xf = xi + vi cos(theta) t
Vertical velocity (not launched at an angle) can be determined by which equation?
vyf = vyi - gt
What are the two things we generally assume about projectile motion?
1. air resistance is negligible
2. acceleration due to gravity is constant and directed downward with a magnitude of 9.81 m/s^2
A train is coasting forward at 20 m/s. A conductor on the train is walking in the forward direction at 2.5 m/s relative to the train. What is the conductor's speed relative to the ground?
22.5 m/s
At the peak of a projectile's trajectory, is the velocity horizontal or vertical?
Horizontal ONLY
If you were to throw a rock 4.3 m/s, horizontally, and drop another from the same height, which would hit the ground first?
Neither, they would hit the ground at the same time
For an upwardly launched projectile, _______ is the best angle to shoot a projectile the furthest distance.
45 degrees
If a tennis ball takes 4.5 sec to reach its peak, how long does it take to reach the other player?
9 seconds
What are the lengths of the x and y components of the resultant vector of the following vectors: Vector A is 25 m and points in a direction 20 degrees below the horizontal. Vector b is 12 m and 45 degrees above the horizontal.
x component: 31.98 m
y component: 0.09 m