Report 1: Objective: To use a micrometer caliper and a Vernier caliper to accurately measure five different objects.
Theory: The precision of length measurements may be increased by using a device that uses a sliding Vernier scale. Two such instruments that are based on a Vernier scale which you will use in the laboratory to measure lengths of objects are the Vernier calipers and the micrometer screw gauge. These instruments have a main scale (in millimeters) and a sliding or rotating Vernier scale. In figure 1 below, the Vernier scale (below) is divided into 10 equal divisions and thus the least count of the instrument is 0.1 mm. Both the main scale and the Vernier scale readings are taken into account while making a measurement. The main scale reading is the first reading on the main scale immediately to the left of the zero of the Vernier scale (3 mm), while the Vernier scale reading is the mark on the Vernier scale which exactly coincides with a mark on the main scale (0.7 mm). The reading is therefore 3.7 mm.
Material and setup: We used the Vernier caliper and the micrometer in order to make correct measurements of the materials below.
Eraser:
1. 2.21
2. 2.20
3. 2.36
4. 2.36
5. 2.26
Coin:
1. 0.2
2. 0.21
3. 0.2
4. 0.3
5. 0.29
Battery:
1. 1.75
2. 1.65
3. 1.7
4. 1.72
5. 1.74
Wooden block:
1. 2.24
2. 2.35
3. 2.38
4. 1.61
5. 2.12
Ring:
1. 2.01
2. 2.02
3. 2.01
4. 2.15
5. 2.11
Material:
Vernier Caliper
Micrometer Caliper
Eraser
Coin
Battery
Wooden block
Ring
Report 2 Objective:
1. Demonstrate the addition of several vectors to form a resultant vector using a force table.
2. Demonstrate the relationship between the resultant of several vectors and the equilibrant of those vectors.
Theory: Physical quantities that can be completely specified by magnitude only are called scalars. Examples include temperature, volume, and time interval. Some physical quantities have both magnitude and direction, and these are called vectors. Examples include velocity and force.
Material and setup:
- Force table with pulleys
- Ring
- String
- Mass holder
- Slotted masses
Procedure:
- Place a pulley at the 30' mark on the force table and place a total of 0.35 Kg (including the mass holder) on the end of the string. Calculate the magnitude of the force (in N) produced by the mass.
- Place a second pulley at the 130' mark on the force table and place a total of 0.25 Kg on the end of the string.
- Determine by trial and error the magnitude of mass needed and the angle at which it must be located for the ring to be centered on the force table. Jiggle the ring slightly to be sure that this equilibrium condition is met. Attach all strings to the rings so that they are directed along a line passing through the center of the ring. All the force will then act through the point at the center of the table.
- Calculate the force produced (mg) on the experimentally determined mass. Record the magnitude and direction of this equilibrant.
- The resultant FR is equal in magnitude to FE, and its direction is 180Ā° from FE. Record the magnitude of the force FR, the mass equivalent of this force, and the direction of the force in data table 1 in the row labeled Resultant FR.
Result:
Report 3 Objective:
1. To study the motion of a body undergoing free fall.
2. To measure experimentally the acceleration due to gravity.
Equipment needed:
- Meter stick
- Metal ball
- Stopwatch
Introduction: A free-falling object is an object that is falling under the sole influence of gravity. Any object that is being acted upon only by the force of gravity is said to be in a state of free fall. There are two important motion characteristics that are true of free-falling objects:
- Free-falling objects do not encounter air resistance.
- All free-falling objects (on Earth) accelerate downwards at a rate of 9.8 m/s^2 (often approximated as 10 m/s^2 for back-of-the-envelope calculations)
Procedure:
1. From a certain height, drop a metal ball. Using a stopwatch, determine the time it will take the metal ball to reach the floor. Record the time for three trials.
2. Do the same for 2 more heights.
3. Record all observations on table A, B, C by using different balls.
4. Determine the percentage error for the average acceleration due to gravity for each table. The percentage error = ((experimental value - accepted value) / accepted value) * 100%
Result:
Rubber ball:
TIME Height(m) Trial1 Trial2 Trial3 average ACC M/S^2
1M 0.45 0.4 0.6 0.48 8.68
1.5M 0.51 0.53 0.52 0.52 11.09
2M 0.56 0.59 0.9 0.68 8.65
Metal ball:
TIME Height(m) Trial1 Trial2 Trial3 average ACC M/S^2
1M 0.35 0.37 0.45 0.39 13.14
1.5M 0.68 0.55 0.41 0.54 10.28
2M 0.63 0.68 0.73 0.68 8.65
Dillon ball:
TIME Height(m) Trial1 Trial2 Trial3 average ACC M/S^2
1M 0.51 0.5 0.43 0.48 8.68
1.5M 0.5 0.43 0.4 0.44 15.49
2M 0.56 0.4 0.62 0.52 14.79
ACCELERATION DUE TO GRAVITY: G = 2d/t^2
Questions and Problems:
1. What is the percentage error on each of the velocities in your experiment? Discuss with your members what could have caused this error. (15 marks)
2. How is the loss in the kinetic energy manifested by the ball each time it reaches the ground? (10 marks)
3. In your experiment, calculate the kinetic and potential energies when the ball was on its midway down the first, the second, and the third time. What can you conclude about the total mechanical energy of the ball as it falls down to the ground? (15 marks)