Junior 2 Physics Final Questions, Junior 2 Physics Volume 1 Final Exam Questions

Do different references for the same thing move the same way?

Answer: The local temperature is 15, the speed of sound in iron is 5200m s, the speed of sound in air is 340m s, the length of the iron pipe is x, and the time difference between the two sounds is: x 340-x 5200=

The solution is: x = meters.

Then the length of this iron pipe is meters.

That's it!

The first time A hears a sound is the sound propagating in iron, and the second time he hears a sound propagating in the air, and let the length of the iron pipe be x, the equation x 340-x 5200 = the speed of sound propagation in the air at 15 degrees Celsius is 340m s), and the solution x is approximately equal to.

A and B heard the echo twice because the first time it was from the iron pipe, and the second time it came from the air.

v null = 340m s

S iron v empty - s iron v iron =

S iron 340m s-s iron 5200m s = the solution of s iron is approximately equal to.

Sound travels at a velocity vt in iron

Airborne propagation velocity vk

The speed difference is v (do the math yourself, I forgot how much the speed of sound is 340?) The length of the iron pipe l=v*t

Is it an exercise? Or do you want you to take the test tomorrow???

The total power is the sum of the working rate of all electrical appliances: 40 * 3 + 100 * 2 + 300 = 620W

Current: p=ui; i=p/u=620/220=

w=pt=620*4*3600=degrees) is: 8928000j

The total power of the circuit is p = 300 + 100 + 40 = 440W

Total current i = p u = 440 220 = 2a

Working an average of 4 hours a day, Xiao Ming's daily electricity consumption is p*t=440*4=1760w*h=kWh.

1、d2、b

3、b4、d

5、a6、d

7、b8、a

9、c10、b

2. Multiple choice questions.

11、a、c、d

12、b、c

13、a、c、d

14、a、b、d

3. Fill-in-the-blank questions.

Rest. Movement 17,

18. Sublimation. Solidify °

24. Smaller.

Smaller 25, 4, drawing and short answer questions.

27. Diagram omitted.

28. The buoyancy of an object immersed in liquid (water) is equal to the gravitational force of its discharging liquid (water).

5. Experimental questions.

29、(1)3v，；(2) Figures omitted.

30. Experimental steps: (1) Let the trolley start to slide down from the top of the inclined plane A until it hits the baffle C, and measure the time t1 of the trolley moving from point A to point C

2) Let the trolley start to slide from the top of the inclined plane A until it hits the baffle C, and measure the time t2 of the trolley moving from point B to point C

3) The distance S1 of the AC section and the S2 of the BC section were measured respectively.

4) By. The average speeds were calculated as:

**:Road. Duration of exercise.

Average. s1=t1=

v1=s2=

t2=v2=

Or: the number of experimental distances.

Exercise time. Average speed 12