"Measurement of Average Speed" Simple Movement of Matter PPT Courseware

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"Measurement of Average Speed" Simple Movement of Matter PPT Courseware

[Experience] Changes in the speed of moving objects and average speed

Activity 1: Ride a bicycle freely down the slope and feel the change in speed.

Activity 2: Xiao Ming is testing the 100-meter race on the playground.

(1) During the process of riding a bicycle down the top of the slope, the speed of the bicycle ________ (optional "increase", "decrease" or "unchanged").

(2) When Xiao Ming ran the middle distance, his speed ________ (optional "change" or "unchanged").

(3) To measure the speed of a bicycle or Xiao Ming, you can use ________ to measure distance, ________ to measure time, and ________ to find the average speed.

Tips: (1) Make it bigger (2) Fill in according to the actual situation

(3) Tape measure, stop watch

pre-study questions

1. What are the physical quantities measured in this experiment?

2. What is the formula for calculating average speed?

Explore Measuring the average speed of motion

Consider the following questions based on the activities in “Experience”

1. Experimental principle: _________.

Tip: In this research experiment, it is necessary to measure the distance s traveled by the person and the time t taken to pass this distance, and then use the average speed formula ___ to calculate the average speed, so the experimental principle is ___.

Reference answer: v=s/t

2. Experimental design: Measure the distance of 30m, mark every 10m, and stand a timekeeper with _______ in hand.

Reference answer: stop watch

Knowledge summary

1. Measurement of average speed

1.Principle:_____.

2. Physical quantities to be measured: _____ and _____.

3.Measurement tools

(1) Distance measurement: _____.

(2) Time measurement: _____.

2. Experiment report

Content included: Experiment title, purpose of experiment, ______, simple _________, records of _______ (generally presented in tables), experimental results, etc.

[Extension] As shown in the picture, the dot timer is a tool for measuring time. The paper tape driven by the moving object passes through the dot timer, and the points marked on the paper tape record the time of the object's movement. The points on the paper tape also represent the position of the moving object at different times. By studying the intervals between points on the paper tape, you can analyze the movement of the object.

Test Points Experimental Research on the Movement Speed ​​of Objects

[Typical example] (2012 Weifang High School Entrance Examination) In order to save raw materials and make it easier for users to use, mosquito coil manufacturers must produce various mosquito coils with different specifications according to the burning speed of mosquito coils. There is a kind of mosquito-repellent incense as shown in the picture. Please design an experiment to measure the normal burning speed of the mosquito-repellent incense. The requirements are:

(1) Write down the required equipment;

(2) Explain the measurement method.

[Guidance of ideas] The key to solving the problem: clarify the physical quantity that needs to be measured, that is, the length of a small section of mosquito coils and the time required to burn this small section of mosquito coils. The equipment is determined by the physical quantities that need to be measured.

[Concise Lecture and Analysis] This question examines the experimental investigation of the speed of objects.

(1) According to the speed calculation formula v=s/t, to measure the normal burning speed of mosquito-repellent incense, it is necessary to measure the length of mosquito-repellent incense burning and the corresponding burning time; measuring the length requires a scale and thin cotton thread, and measuring the time requires a stopwatch. , Regarding the experiment on mosquito-repellent incense, there should be mosquito-repellent incense, and matches must be used to light the mosquito-repellent incense;

(2) Since mosquito coils are spirally coiled, the length must be measured using the method of converting curves into straight lines. Specific method: ① Take a small piece of mosquito-repellent incense, use a thin cotton thread to stick it closely to the mosquito-repellent incense, mark the two end points, straighten the cotton thread, and use a scale to measure the distance between the two marks as s; ② Use a match to light the mosquito-repellent incense and time it. The time it takes for the mosquito-repellent incense to burn out completely is t; ③Then the burning speed of mosquito-repellent incense is v=s/t.

Answer: (1) Equipment: scale, thin cotton thread, stopwatch, mosquito-repellent incense, matches; (2) Measurement method: ① Take a small section of mosquito-repellent incense, use thin cotton thread to stick it closely to the mosquito-repellent incense, mark the two end points, and straighten the cotton thread. Use the scale to measure the distance between the two marks as s; ② Light it with a match

The mosquito-repellent incense is measured and timed, and the time it takes for the mosquito-repellent incense to burn out completely is measured as t; ③Then the burning speed of the mosquito-repellent incense is v=s/t.

1. In an experiment to measure the average speed of an object, if the measured movement time of the object is

If the actual value is large, the measured average speed of the object ()

A. Larger than the actual value B. Same as the actual value

C. Smaller than the actual value D. Uncertain

[Analysis] Choose C.

From the meaning of the question, the measured total distance s is accurate, and the measured movement time t is too large. According to the formula v=s/t, it can be seen that the measured average speed of the object is smaller than the actual value, so choose C.

2. Tianyou uses the following four methods to measure the average speed of the ball rolling along the table. Which one do you think is the best? ()

A. First select a longer distance and measure the time it takes for the ball to pass through this distance.

B. First select a shorter distance and measure the time it takes for the ball to pass through this distance.

C. First select a longer period of time and measure the distance traveled by the ball during this period.

D. First select a short period of time and measure the distance traveled by the ball during this period.

[Analysis] Choose A. It is best to choose a physical quantity with a larger range to measure the average speed, so the error will be smaller. If you select a longer time, the distance traveled by the ball during this period may exceed the length of the tabletop, so you should select a longer distance within the length of the tabletop, and then measure the time. Therefore, you should choose A.

3. (2012 Enshi High School Entrance Examination) Use an inclined plane and a slider to do the "Measuring the Average Speed ​​of an Object" experiment. When the slider starts from the top, the timing starts and stops when it slides to the bottom of the inclined plane, as shown in the figure. During this process, the average speed of the slider is ()

A.10cm/s　B.9cm/s

C.8cm/s D.7cm/s

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"Measurement of Average Speed" Simple Movement of Matter PPT Courseware 3:

"Measurement of Average Speed" Simple Movement of Matter PPT Courseware 3 Knowledge Review How many methods are there to compare the speed of an object's motion? What is the physical meaning of speed? What is the definition? Unit of speed, formula. What is uniform linear motion? Find the common factor of average speed..

"Measurement of Average Speed" Simple Movement of Matter PPT Courseware 2:

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Update Time: 2024-07-29

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