Projectiles

Question 1

A projectile is an object that moves through the air,
along a _______ without a _________ system.

Answer 1

trajectory; propulsion

Question 2

true or false: rocks are projectiles

Answer 2

true

Question 3

true or false: bullets are projectiles

Answer 3

true

Question 4

true or false: rockets are projectiles

Answer 4

false

Question 5

true or false: paper airplanes are projectiles

Answer 5

true

Question 6

true or false: planes are projectiles

Answer 6

false

Question 7

Projectile Motion is motion with a __________________ combined with a _________________ caused by gravity.

Answer 7

constant horizontal velocity; constant vertical acceleration

Question 8

What forces act on a projectile once it is
air-born?

Answer 8

only gravity

Question 9

for all projectiles, there is an acceleration downward of _______

Answer 9

9.8 m/s2

Question 10

The horizontal component of projectile velocity is _______

Answer 10

constant

Question 11

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

Answer 11

instantaneous horizontal velocity

Question 12

The horizontal and vertical motion of a projectile are independent of each other, except they have a
______________

Answer 12

common time

Question 13

Projectiles basically move in two directions 🡪

Answer 13

Horizontally ( the x direction) and Vertically
(the y direction)

Question 14

The horizontal displacement of a projectile is
called the _____________

Answer 14

horizontal range (Δx)

Question 15

Vertical motion happens in the __________.

Answer 15

y-direction

Question 16

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

Answer 16

false

Question 17

projectile motion

Answer 17

the motion of an object that moves in response
to gravity

Question 18

range

Answer 18

the horizontal distance a projectile travels

Question 19

time of flight

Answer 19

the time it takes a projectile to complete its motion

Question 20

At what angle should you launch a projectile from the ground so that it has the
(a) greatest time of flight?

Answer 20

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.

Question 21

At what angle should you launch a projectile from the ground so that it has the
(b) greatest range, assuming no air resistance?

Answer 21

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.

Question 22

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?

Answer 22

horizontal accelerations at all heights: none
vertical accelerations at all heights: 9.8m/s^2(down)

Question 23

true or false:

the initial hor. velocity is always the same as the final hor. velocity

Answer 23

true

Question 24

true or false:

the acceleration at the top of the projectile’s flight path is zero

Answer 24

false

9.8 m/s^2 [down]

Question 25

true or false:

the initial vertical velocity is always the same as the final vertical velocity

Answer 25

false

Question 26

true or false:

the vertical velocity at the top of the projectile’s flight path is always zero

Answer 26

true

Question 27

true or false:

the acceleration of the projectile in the hor. (x) direction is 9.8 m/s^2

Answer 27

false

Question 28

true or false:

a bird flying through the sky is an example of a projectile

Answer 28

false

Question 29

true or false:

a ball that is thrown through the air is an example of a projectile

Answer 29

true

Question 30

true or false:

for projectile motion, there is a positive acceleration in the x direction

Answer 30

false

Question 31

true or false:

for projectile motion, the final velocity is always zero

Answer 31

false