Projectiles Flashcards
A projectile is an object that moves through the air,
along a _______ without a _________ system.
trajectory; propulsion
true or false: rocks are projectiles
true
true or false: bullets are projectiles
true
true or false: rockets are projectiles
false
true or false: paper airplanes are projectiles
true
true or false: planes are projectiles
false
Projectile Motion is motion with a __________________ combined with a _________________ caused by gravity.
constant horizontal velocity; constant vertical acceleration
What forces act on a projectile once it is
air-born?
only gravity
for all projectiles, there is an acceleration downward of _______
9.8 m/s2
The horizontal component of projectile velocity is _______
constant
whatever the initial horizontal velocity of the projectile is, that will be the exact same as the ______________ at any point in the projectile’s motion
instantaneous horizontal velocity
The horizontal and vertical motion of a projectile are independent of each other, except they have a
______________
common time
Projectiles basically move in two directions 🡪
Horizontally ( the x direction) and Vertically
(the y direction)
The horizontal displacement of a projectile is
called the _____________
horizontal range (Δx)
Vertical motion happens in the __________.
y-direction
true or false:
When two objects are dropped from the same height at the same time, the heavier object will land first when there is no air resistance
false
projectile motion
the motion of an object that moves in response
to gravity
range
the horizontal distance a projectile travels
time of flight
the time it takes a projectile to complete its motion
At what angle should you launch a projectile from the ground so that it has the
(a) greatest time of flight?
To give a projectile the greatest time of flight, launch it at 90° from the ground because this angle maximizes the vertical component of the velocity. At 90° from the ground, all the velocity is straight up, instead of some of the velocity going into the horizontal component.
At what angle should you launch a projectile from the ground so that it has the
(b) greatest range, assuming no air resistance?
To give a projectile the greatest range,
launch it at 45°. If the angle is less than 45°, the
flight will be too short to travel any farther.
A field hockey ball is launched from the ground at an angle to the horizontal. What are the ball’s horizontal and vertical accelerations
(a) at its maximum height?
(b) halfway up to its maximum height?
(c) halfway down to the ground?
horizontal accelerations at all heights: none
vertical accelerations at all heights: 9.8m/s^2(down)
true or false:
the initial hor. velocity is always the same as the final hor. velocity
true
true or false:
the acceleration at the top of the projectile’s flight path is zero
false
9.8 m/s^2 [down]
true or false:
the initial vertical velocity is always the same as the final vertical velocity
false
true or false:
the vertical velocity at the top of the projectile’s flight path is always zero
true
true or false:
the acceleration of the projectile in the hor. (x) direction is 9.8 m/s^2
false
true or false:
a bird flying through the sky is an example of a projectile
false
true or false:
a ball that is thrown through the air is an example of a projectile
true
true or false:
for projectile motion, there is a positive acceleration in the x direction
false
true or false:
for projectile motion, the final velocity is always zero
false
