![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
After braking, the moving car moves in a straight line with uniform deceleration and stops in 3.5 seconds. The ratio of the displacement that it passes in 1 second, 2 seconds and 3 seconds after braking is () A. 1：3：5B. 3：5：7C. 1：2：3D. 3：5：6
The schematic diagram is as shown in the figure. The car's uniformly decelerated linear motion with the final speed of 0 from a to e is reversed and converted into a uniformly accelerated linear motion with the initial speed of 0 from e to a for equivalent treatment. Because the acceleration is the same before and after the reversal, the motion displacement and speed time before and after the reversal are symmetrical. Therefore, it is known that the displacement ratio of the car in the same time is 1:3 ：5：… So xde: XCD: XBC: XAB = 1:8:16:24, so XAB: XAC: XAD = 3:5:6. So option D is correct
RELATED INFORMATIONS
- 1. If the displacement in the second second second after braking is 6.25m (the braking time is more than 2S), then (1) what is the acceleration of the vehicle? (2) What is the displacement of vehicle passing through in 6 seconds after braking?
- 2. What is the displacement ratio of a car moving along a straight line after braking, decelerating and taxiing evenly and stopping in 3.5 seconds
- 3. If the displacement is 6 meters in the first second and 2 meters in the last second before stopping, then: (1) during the whole deceleration If the displacement in the first second is 6 meters and that in the last second before stopping is 2 meters, then: (1) what is the displacement of the car in the whole deceleration process? (2) how much time does the whole deceleration process share?
- 4. After braking, the car moving at a uniform speed of 10m / s moves in a straight line with uniform deceleration. The displacement within 2S after braking is 6.25m, and that within 6S after braking is 6.25m
- 5. After entering the station, the car starts to brake and decelerate in a straight line. In the first second, the displacement is 9 m and 7 m respectively After entering the station, the car starts to brake and make a uniform deceleration linear motion. The displacement in the first second is 9m and 7m in turn. Then what is the displacement in the sixth second after braking? Why can we use the displacement difference 2m to get 9,7,5,3,1,0m? Why is it 0m in the end
- 6. Because of the brake, the car starts to make uniform deceleration linear motion at the speed of 10m / s. if the average speed in the first second is 9m / s, what is the displacement of the car in the first 7S?
- 7. When a bus comes into the station, it starts to brake and make a uniform deceleration linear motion. The displacement in the first second and the second second is 9m and 7m respectively, then the displacement in the sixth second after braking is () A. 20 mB. 24 mC. 25 mD. 75 m
- 8. The average speed in the third second is 9 m / s. find (1) the acceleration of the uniform deceleration of the car (2) the displacement of the car in 10 s
- 9. The car starts to brake at the speed of 10m / s, the acceleration is 2m / S2, and the displacement ratio of 3S, 2S and 1s before stopping is calculated
- 10. When a car moves forward at a speed of 10m / s and the acceleration is 2.5m/s2 after braking, what is the displacement in 3S? What is the displacement within 10 seconds after braking?
- 11. When an object moves in a straight line with a uniform acceleration of 2m / s and the displacement in the second second is 12M, the initial velocity of the object is
- 12. The displacement of an object in the second second second is 10 m,
- 13. When an object is accelerating uniformly, the initial velocity is 0.5m/s, and the displacement in the second second second is 4m more than that in the first second It can be calculated with △ x, but why can't it be calculated with x = v0t + 0.5at ^ 2
- 14. The initial velocity of the object is V0 = 5m / s, the initial acceleration is A1 = 4m / s # 178;, and the acceleration becomes A2 = 2m / s # 178; after moving for 2S What are the velocities at the end of 1s, 2S, 3S and 4S? The acceleration a decreases but the velocity V increases. Why?
- 15. When an object moves in a variable speed linear motion, the velocity is 4 m / s at a certain moment, and the velocity after 2 s is 4 m / s. if the acceleration of the object is constant within 2 s, then the acceleration of the object is constant A / may be equal to 0 B / may be less than 4m / S C / must be 4 m / s D / may be greater than 4m / s
- 16. When an object moves in a straight line with constant speed, the velocity at a certain moment is V1 = 4m / s. after t = 2S, the velocity becomes V2 = 8m / s, and the acceleration a of the object is calculated
- 17. When an object is moving in a straight line with uniform speed change, the velocity is 4m / s and 178; at a certain time. After 2 seconds, the velocity becomes 8m / s and 178; to calculate the acceleration of the object
- 18. A. Car B stops at the same place. At a certain moment, car a starts at a constant acceleration of 2m / S ^ 2. After 2 seconds, car B starts at a constant acceleration of 4.5m/x ^ 2 in the same direction (1) How long does car B leave to catch up with car a? (2) Before car B overtakes car a, what is the maximum distance between the two cars? Draw a V-T image
- 19. When an object moves in a variable speed linear motion, the velocity is 4 m / s at a certain moment, and becomes 10 m / s after 2 seconds, then the average acceleration of the object in these 2 seconds is less than 10 m / s? Why? I know the answer 3m / S2 and 7m / s2
- 20. When the acceleration is 2 m / S2 and the displacement is 20 m in the first four seconds, the initial velocity is 0___ M / s, the initial velocity in the second second second is___ m/s The acceleration is 2m / S2 and the displacement is 20m in the first four seconds Then the initial velocity is______ m/s, The velocity at the beginning of the second second is______ m/s, The final velocity in 4S is______ m/s, The ratio of the first 2 s displacement to the second 2 s displacement is 0______