Amali Fizik - Lecture notes 1 PDF

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SFL1013 TECHNIQUES IN PHYSICS LABORATORYDEPARTMENT OF PHYSICSFACULTY SCIENCE AND MATHEMATICSLab ReportNAME ANDID NUMBERNUR ILYA SYAMIRA BT ALIASEGROUP CLECTURER Dr. Ahmad Kamal bin AriffinEXPERIMENT NO. Laboratory 3EXPERIMENT TITLE Reaction Time and Gravitational AccelerationEXPERIMENT DATE 22 March...

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SFL1013 TECHNIQUES IN PHYSICS LABORATORY DEPARTMENT OF PHYSICS FACULTY SCIENCE AND MATHEMATICS Lab Report

NAME AND ID NUMBER

NUR ILYA SYAMIRA BT ALIAS E20201026007

GROUP

C

LECTURER

Dr. Ahmad Kamal bin Ariffin

EXPERIMENT NO.

Laboratory 3

EXPERIMENT TITLE

Reaction Time and Gravitational Acceleration

EXPERIMENT DATE

22 March 2021

SUBMISSION DATE

29 March 2021

1. ABSTRACT A statistical decision theory of simple RT is outlined. The theory is based on the view that simple reactions are prepared responses elicited by the triggering of a response release mechanism which can be pre-set by S, and treats S's setting of this mechanism as a statistical decision process. The simple pendulum experiment aim is to investigate how the period of oscillation relates to the displacement angle and to find the gravitational acceleration due to the gravity of a swinging object about a point. The gravitational pull on the mas object was done by manipulation of the length of the bob from the fixed point O and the angular displacement 5 degrees. There were some assumptions which were made during the experiment to guide the analysis. These assumptions are: the only effective mass is that of the bob, the maximum attainable displacement angle is very small and that the string is inextensible. The mass of the pendulum was found not to affect the periodic time of oscillations.

2. INTRODUCTION

I.

Purpose

1. To measure your personal reaction time 2. To measure the acceleration due to gravity using a simple pendulum method 3. To find the relation of T and L of a simple pendulum. II. Theory A simple pendulum consists of a mass m hanging from a string of length L. When displaced to an initial angle and released, the pendulum will swing back and forth with periodic motion. By applying Newton's secont law for rotational systems, the equation of

motion for the pendulum may be obtained. If the amplitude of angular displacement is small enough that the small angle approximation holds true, then the equation of motion reduces to the equation of simple harmonic motion 3. APPARATUS 15cm ruler, stop watch, stone, protector and shoelace.

4. PROCEDURE

A. Simple Reaction Time 1. Work with partner. 2. The partner hold out his/her hand with a gap between thumb and first finger. You holds the ruler with the zero at the top of your thumb as shown in Fig. 1. 3. Challenge your partner to catch the ruler by snapping his/her shut when you release the ruler as shown in Fig. 2. You drops the ruler without telling your partner he/she must catch it. Measure and record times, t and distance, d in the table 1. 4. Then, swap places, and repeat step 1 to 3 again.

Figure 1

Figure 2

The process of catching a ruler to test reaction speeds

B. Simple Pendulum 1. Prepare a stone and shoelace. Tie them together and hang as shown in Figure 3. 2. Measure the length of string, L of the pendulum and record it in the Table 2. 3. Displace the pendulum at a small angle (around 5 degrees). Measure the time period for the pendulum swing back and forth for 10 times. Record it in the Table 2. Repeat this step 3 times. 4. Repeat the procedure using 3 different length, L and record in the Table 2. 5. Draw a suitable graph that can reveal the relation between T and L. Calculate the value of g and show your work clearly.

Figure 3 The process of swinging the pendulum

5. DATA AND OBSERVATIONS A. Simple Reaction Time

Table 1: Distance of the ruler, d and time, t.

Person

Distance of ruler, d (cm) ± 0.1

Average , d (cm)

Times taken, t (s) ± 0.01

Average, t (s)

A

7.0

5.0

7.5

6.5 ± 0.1

0.25

0.42

0.67

0.45 ± 0.1

B

9.5

7.0

6.5

7.7 ± 0.1

0.69

0.65

0.52

0.62 ± 0.1

B. Simple pendulum Table 2: Length of pendulum string, L and period, T.

Length, L (cm)

Period, T (s) ± 0.01

Average (s)

1

2

3

10

7.22

7.46

8.03

7.57 ± 0.01

20

11.17

10.72

10.90

10.93 ± 0.01

30

11.94

12.12

12.02

12.02 ± 0.01

6. ANALYSIS - Graph, Calculations, Result Graph 1: Relation between period, T against length of string, L

This graph show that period, T is perpendicular to length of pendulum string, L

A. Simple Reaction Time Calculations Reaction time person A: t = √ (2 x 6.5cm / 980cms²) t = 0.12 s ± 0.1 s Reaction time person B: t = √ (2 x 7.7cm / 980cms²) t = 0.13 s ± 0.1 s These calculations shown that reaction time Person A is faster then Person B

Reaction Time Questions 1. Is the reaction time constant? If not, suggest possible explanations why reaction times are different for different people. -

No, everyone has a different reaction time because not everyone reacts the same to situations. Some people may be faster or slower than others. Many factors have been shown to affect reaction times, including age, gender, and physical fitness.

2. Will the reaction time significantly affect measurements you might make using instruments for this course? How could you minimize its effect? -

Yes, you could minimize its role by just being aware of it, and working on reflexes as well as video recording labs that require timing so you can go back and make sure the time was as accurate as possible.

3. What role does reaction time play in applying the brakes to a car in an emergency? Estimate the distance a car travels at 110 km/h during your reaction time in braking. (Show your calculation). -

Reaction time can play a huge role when applying the brakes to your car in an emergency situation because it can save you from hitting whatever is in front of you. The faster your reaction time, the less distance you will travel before you hit the brakes. = 110km/h x 1000m/1km x 1h/60min x 1min/60s = 30.556 m/s d = ½ at = ½ (30.556/s) (6.5s)² = 645.50 m

Simple Pendulum Questions 1.

What role, if any, does air resistance have on your results? Explain your reasoning. -

When air resistance acts, acceleration during a fall will be less than g because air resistance affects the motion of the falling objects by slowing it down. Air resistance depends on two important factors - the speed of the object and its surface area. Increasing the surface area of an object decreases its speed.

2. Would you conclude that Galileo was correct in his observation that the period of a simple pendulum depends only on the length of the pendulum? -

3.

No, the time period of a simple pendulum depends upon the length of the pendulum (L) and acceleration due to gravity (g) at the place of doing the experiment by the expression : T = 2 π √l/g

On the moon, the acceleration due to gravity is one-sixth that of earth. �oooo � = �eeℎ 6

What effect, if any, would this have on the period of a pendulum of length L? How would the period of this pendulum differ from an equivalent one on earth? Calculate one example from your data. g earth (from calculations) = 980 ms-² g moon = 980 ms-²/6 g moon = 163.3 ± 0.1 ms-² T = 2π √ (30cm/12.02 ms-²) T = 9.93 ± 0.1 s

7. CONCLUSION From the experiment, the data collected enabled the determination of the relationship between the periods of oscillation of a simple pendulum with its length from the Centre the swing, which increases with the length. The period also varies as a square of the length of the pendulum.For better results and accuracy in the analysis, the discussed errors could be minimized by reducing the reaction time of the observer, digitally programmed equipment for recording data could be used to improve on the accuracy of results.

8. REFERENCES https://phet.colorado.edu/sims/html/pendulum-lab/latest/pendulum-lab_en.html https://brainly.in/question/3429218...