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If the speed of car a and car B is equal, and the car decelerates evenly after braking, then the distance of car B is () A. 9 mB. 18 mC. 36 mD. 72 m
Let the initial velocity of a and B be v0. According to the inference of the average velocity, the displacement of a is X1 = v02t1, that is, 18 = V02 × 3. The displacement of B is x2 = v02t2 = V02 × 1.5. The simultaneous solution of the two equations gives x2 = 9m. So a is correct and B, C and D are wrong
The speed of a and B vehicles is equal. After braking at the same time, both vehicles are set to decelerate evenly. When a stops for 3 seconds and B stops for 1.5 seconds, the forward distance of B vehicle is ()
A. 9mb. 18mc. 36md
The average speed of car a is: v = V0 + 02 = 363 = 12m / s, and the initial speed is: V0 = 24m / s. The average speed of car B is: v = V0 + V2 = 12m / s, then the displacement is: x = V × t = 12 × 1.5 = 18m / s. therefore, B is correct, and a, C and D are wrong
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