The displacement of an object is S1 in the first 3 seconds and S2 in the last 3 seconds The displacement of an object in the first 3 seconds is S1, and that in the last 3 seconds is S2. Given s2-s1 = 6m, S1: S2 = 3:7, the total length of the inclined plane can be calculated The slide is accelerating. Let the length of slope be l and the total time be t L=a*t^2 / 2 S1=a *3^2 / 2 S2=L-[ a*( t -3)^2 / 2 ]=3at-4.5a 3/7=(a *3^2 / 2)/(3at-4.5a) T = 5 seconds 6=(3at-4.5a)-(a *3^2 / 2) a=1m/s^2 L = 12.5A = 12.5m
12.5, it's really a bit of trouble, I don't know if it's right
Key uniform acceleration motion, initially and finally for 3 seconds, with the image solution convenient
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- 1. It is known that S2 + S1 = 1.2m, S1: S2 = 3:7, and the total length of the inclined plane is 1.2m?
- 2. The object from the top of the inclined plane from static to the bottom of the inclined plane, the first 3 seconds after the displacement S1 S2 S1 + S2 = 1.2m S1: S2 = 3:7, calculate the length of the inclined plane
- 3. The displacement of an object from the top of the inclined plane to the bottom of the inclined plane is S1 in the first three seconds and S2 in the last three seconds It is known that S1 + S2 = 1.2m, Si: S2 = 3:7 In one step, I can't figure out why v = V 0 + at = 0.28 + 0.08 * 1.5, that 1.5 is. Isn't V 0 the initial velocity? Why can we use the average velocity instead Calculate S1, S2, then a = 0.08, then calculate the average speed in the next 3 seconds = 0.28, then calculate the final speed, calculate t according to v = at, and then substitute t into S = 1 / 2at ˇ 2 to calculate s = 1m, but when calculating the final speed, it is how to calculate v = V0 + at = 0.28 + 0.08 * 1.5, and 0.28 is how to substitute the average speed into the initial speed
- 4. In the formula s = VT + 1 / 2at & # 178;, when t = 1, s = 13; when t = 5, Ms = 225, find the value of s when t = 2
- 5. In the high school physics formula, there is a formula for acceleration: the square of S = at. How can this formula be deduced?
- 6. S = VT + 1 / 2at & sup2; if the time unit is h and the displacement unit is km, how will the formula change?
- 7. The difference between the physical displacement formula s = v0t + 1 / 2at ^ 2 and S = vt
- 8. S = VT + 1 / 2at ^ 2 VT ^ 2-v0 ^ 2 = 2As how can these two formulas be derived Ask for guidance
- 9. S = v0t + 1 / 2at square s = v0t-1 / 2at square what's the physical formula? Why didn't my teacher teach it,
- 10. Why is the displacement formula s = v0t + 1 / 2at ^ 2
- 11. A formula for calculating acceleration by successive difference method in physics of grade one of senior high school (with explanation) I know seven points first, then S4-S1 s5-s2 s6-s3 And then what?
- 12. Take the three sides of RT △ ABC as the edge, make three general triangles outward, and their areas are expressed by S1, S2, S3 respectively, to determine the relationship between S1, S2, S3
- 13. Take the three sides of RT triangle ABC as the diameter and make three semicircles outwards. What is the quantitative relationship between their areas S1, S2 and S3?
- 14. In Fig. 1, three semicircles are made outward with three sides of RT △ ABC as diameters, and their areas are expressed by S1, S2 and S3 respectively. It is not difficult to prove that S1 = S2 + S3. (1) (1) As shown in Figure 2, take the three sides of RT △ ABC as the sides and make three squares outward, and their areas are represented by S1, S2 and S3 respectively. Write down their relationship. (it is not necessary to prove) (2) As shown in Figure 3, take the three sides of RT △ ABC as the edges and make regular triangles outward, and their areas are represented by S1, S2 and S3 respectively. Determine their relationship and prove it; (3) If three general triangles are made outward with three sides of RT △ ABC, and their areas are expressed by S1, S2 and S3 respectively, what conditions should be satisfied for the triangle to have the same relationship with (2) between S1, S2 and S3?
- 15. As shown in the figure, take the three sides of RT △ ABC as the sides and make three equilateral triangles outwards. Their areas are represented by S1, S2 and S3 respectively. Please guess the quantitative relationship between S1, S2 and S3 and explain the reason
- 16. As shown in the figure, △ ABC is a right triangle, S1, S2 and S3 are squares, a, B and C are known to be the side lengths of S1, S2 and S3 respectively, then () A. b=a+cB. b2=acC. a2=b2+c2D. a=b+2c
- 17. As shown in the figure, it is known that in △ ABC, ∠ ACB = 90 °, take each side of △ ABC as an edge and make three squares outside △ ABC. S1, S2 and S3 represent the area of the three squares respectively. S1 = 81 and S2 = 225, then S3 = () A. 16B. 306C. 144D. 12
- 18. As shown in the figure, draw three semicircles with the three sides of the right triangle as the diameter. If the areas of the two small semicircles are known to be S1 = 8 and S2 = 18, then S3 =? A.10 B.13 C.26 D.25
- 19. As shown in the figure, the power supply voltage remains unchanged. Close switches S1 and S2, the voltage indication is 6V, and the current indication is 0.6A. After S2 is disconnected, the voltage indication becomes 2V, and the resistance and power supply voltage of R2 are () A. 10Ω、9VB. 20Ω、6VC. 20Ω、9VD. 10Ω、6V
- 20. In the circuit shown in the figure, the power supply voltage remains unchanged. When the switch S1 is closed, the lamp l will light up. If the switch S2 is closed again, then () A. The number of two ammeters increases B. the brightness of light l decreases C. The total resistance of the circuit decreases D. the number of voltmeters increases