PHYS 4A/ Fall 2014; Trajectories

Purpose: To use projectile motion physics in order to predict the impact point of a metal ball on an inclined board.

Set-up: The experiment required to do the experiment consisted of a standing metal rod, a clamp, wooden blocks, two v-channels, a meter stick, a metal ball, and carbon paper. The equipment should be in a set up similar to the one below. The metal ball is then dropped from a point on the v-channel and allowed to roll of the end of the horizontal channel. Where it lands on the floor is where the carbon paper is laid down.

Set-up

Carbon Paper

 The metal ball was rolled several times to test the accuracy of the drop point. The drops were very close to each other. The distance from the end of the table to the impact point on the carbon paper was measured and this information was used to determine the initial velocity of the ball as it left the ramp using kinematics.

 After calculating velocity, the distance that the ball should hit a wooden board at an incline was determined. The angle of the incline was taken using a protractor and incorporated into the calculations. Below is an image of the wooden board.

Calculation for velocity and prediction of how far down the incline the ball will hit the wooden board.

After calculating the distance the ball should travel down the board, the experiment was done again with the board. Using a meter stick, the distance was measured to be 0.673 meters. Uncertainty for the measurements were then calculated for comparison and to see if the results were valid. 

With uncertainty, our experimental distance was 0.673+/- 0.539 meters. This was compared to our theoretical 0.667 meters. There was only +0.9% deviation from the actual value, thus the experiment was successful. A way to improve the experiment and get even less deviation would be to use channels that were friction less or to use a digital protractor to decrease the uncertainty in the angle.