See my notes and please continue the process of revision. Submit a revision when you have completed it.
Collision experiment
Procedure:
Roll a ball down an incline and onto a horizontal incline, from which it will collide immediately after leaving that incline with a small marble supported by a section of straw. The plane normal to the contact surfaces between the two marbles should be vertical and perpendicular to the direction of the first ball's motion. See how far each ball travels after collision before reaching the floor, and use this information to determine the velocity of each ball after the collision. Let the first ball roll down the inclines and off the edge without hitting the second ball. Use your observation of its horizontal range to determine how fast this ball was traveling before the collision. Repeat this five times. Determine `dv_2, the change in velocity of the second ball in the collision. Determine `dv_1, the change in velocity of the first ball in the collision. Using the fact that m2 `dv2 = -m1 `dv1, find the ratio m2 / m1 of the mass of the second ball to the mass of the first ball.
Data:
Undeflected ball Deflected (first ball) Target ball (second ball)
Horizontal fall 29.3 cm 25 cm 61.9 cm
Change of velocity post collision -10.4 cm/s 143.95 cm/s
KE before collision 0.14 Joules 0 Joules
KE post collision 0.07 Joules 0.075 Joules
This gives us 0.14J before and 0.145 J after collision.
You need to explain in detail how you get from the data to the velocities.
Which ball is therefore the more massive?
The magnitude of the change in m v is the same for both. Since the magnitude of the change in v for the second ball is about 5 times that for the first, we conclude that the first has 5 times the mass of the second.
The steel ball has both greater density and greater volume. How much greater is its volume?
(V2 / V1) = (4/3 pi r2^3) / (4/3 pi r1^3) = (r2 / r1)^3, and since the ratio of diameters is the same as the ratio of the radii we see that (V2 / V1) = (d2 / d1)^3 = (25 mm / (18 mm) )^3 = 2.7, approx..
If the steel ball has 5 times the mass and 2.7 times the volume, then what is the ratio of densities of steel and glass?
If the steel ball has 2.7 times the volume and 5 times the mass then it has 5 / 2.7 = 1.8 times the density. The density of steel is about 7.5 grams / cm^3. So the mass of the steel ball is about 60 grams. If the density ratio is 5/1 then the marble has mass about 12 grams.
This explanation appears to be identical to the explanation I gave in class. That should be a basis for your analysis but your analysis has to be based on your data, not on the sample data I used in class.