BACKGROUND      A common use of projectiles in motion is in some sort of weapon. By analyzing the behavior of the motion of a projectile, such as a dart gun, you can use it to make predictions about how projectiles work.

TASK             Design and conduct experiments to determine the location and angle at which to stand, along with your classmates in a circle, in order to fire a nerf dart gun so it exactly hits your physics teacher on the top of the head.

AUDIENCE: Teacher and peers

PURPOSE: To use and apply knowledge of projectiles in motion.

PROCEDURE:

Obtain Materials: nerf dart gun (use the same gun and dart each time) , meter stick, measuring tape, calculator, graph paper, masking tape.

I)   Keeping the gun perfectly horizontal, so its initial vertical (y) velocity is zero, devise a method for accurately determining the “muzzle” velocity of the gun. (You can determine the Dx and Dy)

h

Dx

H=1/2gT2. solve for T  Vx=Dx/T

Also calculate the projectile’s acceleration in the gun.

Conduct your experiment, including several trials and the effects of air resistance.

2. Using your results, practice by determining angle and range to a target several meters away. Keep track of your results. Place a target 1-5 meters away about 2 meters off the ground. Holding the dart at about  .5 meters off the ground, at different angles (20, 40, 50, 60?) calculate using your previous results (so now =Vx), the exact distance away at which you must hold the gun in order to hit the target (on the way up and/or on the way down).

Graph your results, dependent on height, angle, and range to target.

Present your results to the class.

3. Using your formula, calculate how to aim to hit the teacher with the rest of the class.

Holding the gun at a 45 degree angle, calculate where you should stand to directly hit the top of my head as I am seated. (Dy=0, V = muzzle velocity of gun)

Find “your” dart gun. Make sure you know its velocity.

(You did this by firing horizontally at a certain distance…..

V = Dx/T         where T= sqrt ( 2 Dy / Ay ) where Dy is the distance it dropped. )

----------------------------

Immediately calculate Part Three….. Firing at my head with a Dy of 0, angle of 45 degrees.

Dx = 2V2/Ay * sin (45)*cos (45)

Test it out!

Make sure you have a table for each part with measurements and calculations:

I)

Dx (you decide)| Angle(zero!) | Dy (you measure) | T (you calculate) | Vx (you calculate)

II)

Test your gun at different angles, height of target, and distance away and see if physics works!

Show your actual data, and what it should’ve been

Dy (you decide)| Angle(you decide)|V (you know) |T (you calculate) |  Dx (you calculate)

**Honors

Dy (you decide)| Dx (you decide) |V (you know) |T (you calculate) |Angle(you calculate)|

III)

Dy (0)| Angle(45)|V (you know) |T (you calculate) |  Dx (you calculate)

---------------------------------------------------------------

What forces were acting on the dart at each point of its journey?

In the Gun?    On the way up?         On the way down?    When it hit? After?

What do you think those forces depend on? (How could they change?)

How did the force affect the motion of the dart?

------------------------

By the end of class: Have all your measurements…. THEN make sure your data is in a clear table, THEN finish writing your conclusions.

A. PHYSICS

Assessment Points

Points              Earned Assessment:

Element                                                                                  Possible            Self             Teacher

PLANNING

1. Outline of experiment purpose                                    5

_______________________________________________________________________

1. Procedure to determine muzzle velocity                      15

_______________________________________________________________________

1. Data on muzzle velocity (including spring/air resistance)        10

_______________________________________________________________________

1. Explanation of muzzle velocity results                        10

_______________________________________________________________________

1. Overall calculation of range/angle/height for gun        10

_______________________________________________________________________

1. Presentation of results with graph and formulas         10

_______________________________________________________________________

1. Presentation to class, clear, well thought out. 10

_______________________________________________________________________

1. Trial run with target                                                     5

_______________________________________________________________________

1. Final results of firing squad                                        5

_______________________________________________________________________

1. Discussion of validity,error analysis

and conclusions for further study                                     10

_______________________________________________________________________

TOTAL  __90___        _____           _____

BACKGROUND      A common use of projectiles in motion is in some sort of weapon. By analyzing the behavior of the motion of a projectile, such as a dart gun, you can use it to make predictions about how projectiles work.

TASK             Design and conduct experiments to determine the location and angle at which to stand, along with your classmates in a circle, in order to fire a nerf dart gun so it exactly hits your physics teacher on the top of the head.

AUDIENCE: Teacher and peers

PURPOSE: To use and apply knowledge of projectiles in motion.

PROCEDURE:

Obtain Materials: nerf dart gun (use the same gun and dart each time) , meter stick, measuring tape, calculator, graph paper, masking tape.

I)   Keeping the gun perfectly horizontal, so its initial vertical (y) velocity is zero, devise a method for accurately determining the “muzzle” velocity of the gun. (You can determine the Dx and Dy)

h

Dx

H=1/2gT2. solve for T  Vx=Dx/T

Also calculate the projectile’s acceleration in the gun.

Conduct your experiment, including several trials and the effects of air resistance.

2. Using your results, practice by determining angle and range to a target several meters away. Keep track of your results. Place a target 1-5 meters away about 2 meters off the ground. Holding the dart at about  .5 meters off the ground, at different angles (20, 40, 50, 60?) calculate using your previous results (so now =Vx), the exact distance away at which you must hold the gun in order to hit the target (on the way up and/or on the way down).

Also find the correct angle to hold the gun so it hits the target on the way down 2 meters away, 2 meters off the ground.

Graph your results, dependent on height, angle, and range to target.

Present your results to the class.

3. Using your formula, calculate how to aim to hit the teacher with the rest of the class.

Holding the gun at an angle, calculate where you should stand to directly hit the top of my head as I am seated. (Dy=0, V = muzzle velocity of gun)Record and analyze your results!

Find “your” dart gun. Make sure you know its velocity.

(You did this by firing horizontally at a certain distance…..

V = Dx/T         where T= sqrt ( 2 Dy / Ay ) where Dy is the distance it dropped. )

----------------------------

Immediately calculate Part Three….. Firing at my head with a Dy of 0, angle of 45 degrees.

Dx = 2V2/Ay * sin (45)*cos (45)

Test it out!

Make sure you have a table for each part with measurements and calculations:

I)

Dx (you decide)| Angle(zero!) | Dy (you measure) | T (you calculate) | Vx (you calculate)

II)

Test your gun at different angles, height of target, and distance away and see if physics works!

Show your actual data, and what it should’ve been

Dy (you decide)| Angle(you decide)|V (you know) |T (you calculate) |  Dx (you calculate)

**Honors

Dy (you decide)| Dx (you decide) |V (you know) |T (you calculate) |Angle(you calculate)|

III)

Dy (0)| Angle(45)|V (you know) |T (you calculate) |  Dx (you calculate)

---------------------------------------------------------------

What forces were acting on the dart at each point of its journey?

In the Gun?    On the way up?         On the way down?    When it hit? After?

What do you think those forces depend on? (How could they change?)

How did the force affect the motion of the dart?

------------------------

By the end of class: Have all your measurements…. THEN make sure your data is in a clear table, THEN finish writing your conclusions.

H. PHYSICS

Assessment Points

Points              Earned Assessment:

Element                                                                                  Possible            Self             Teacher

Outline of experiment purpose                                                5

_______________________________________________________________________

Procedure to determine muzzle velocity                                  15

_______________________________________________________________________

Data on muzzle velocity (including spring/air resistance)        10

_______________________________________________________________________

Explanation of muzzle velocity results                                    10

_______________________________________________________________________

Overall calculation of range/angle/height for gun                    10

_______________________________________________________________________

Presentation of results with graph and formulas                     10

_______________________________________________________________________

Presentation to class, clear, well thought out.             10

_______________________________________________________________________

Trial run with target                                                                 5

_______________________________________________________________________

Final results of firing squad                                                    5

_______________________________________________________________________

Discussion of validity,error analysis

and conclusions for further study                                     10

_______________________________________________________________________

TOTAL  __90___        _____           _____