Physics Home > Teaching Labs > Mechanics > Projectile Motion

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#### Lab Activities

The motion of a golf ball projectile is analyzed in three ways:

a. graphically using vectors;

b. mathematically using the components of the positions vectors and the equations of uniform motion for the x-direction motion and the equations governing uniformly accelerated motion for the motion in the y-direction; and

c. using the computer to do the same calculations plus do various kinds of plots of the data and least squares fits to the data.

In all three cases, the students check for the following things:

a. that the velocity of the golf ball in the x direction is constant;

b. that the ball is accelerated in the y-direction and that the magnitude and direction of that acceleration is constant; and

c. that the magnitude of the acceleration in the y-direction is 980 cm/sec^2.

The experimental data can be taken in two ways: (1) using a Polaroid camera and a strobe light or (2) using an apple computer and a camera. In the first method the students determine the x and y coordinates of each image of the ball using cylinders and pins and the Polaroid photograph. In the second method, the students are given the coordinates by the computer. Results for g in either case lie within 3% of the accepted value.

As an optional exercise, students can also be asked to analyze the motion of a styrofoam ball which is subjected to a wind in the negative x-direction.

#### Course Level

Introductory: P3, P13, P15

#### Equipment

 Number of set-ups available: Per lab station: 1 rulers (1 per student) 1 protractors (1 per student) 1 triangles (1 per student) 1 roll of masking tape 1 golf ball projectile 1 styrofoam ball 1 ping pong ball sample data 10 X 10 grid paper 1 ball catching box 1 brass ball launching tube 1 allen wrench 12 lead bricks 2 Apple II+ data aquisition system containing: 1 Apple II+ computer 2 monitors 1 video camera 1 imagewriter printer/paper 2 AppleStrobe software disks 1 large black box on wheels 1 large white calibration disk 3 True Basic Reference Manual 3 True Basic User's Manual

#### Notes

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