A car moves on a straight road at an initial speed of 6m / s, and the acceleration after braking is 2m / S & sup2; How large is the displacement of the car within 2 seconds after braking? ② What is the displacement of the car within 8s after braking?

When braking, the car moves in a straight line with uniform deceleration, which is equivalent to acceleration a = - 2m / S2. When braking, first judge when to stop, V0 + at = 0 = > t = 3 seconds, stop for 1, and the car hasn't stopped in 2 seconds, so the displacement in 2 seconds = v0t + 0.5at2 = 6 * 2 + 0.5 * (- 2) * 2 ^ 2 = 8m2. When braking in 8 seconds, the car stops, so the displacement in 8 seconds and 3 seconds is one

When a car with uniform acceleration passes through two power poles on the road, it takes five seconds. The acceleration of the car is 2m / s and the speed of the car passing through the second power pole is 15m / s, so the speed of the car passing through the first power pole is 2m / s
The answer is 5m / s and 178;

V1=V2-AT=15-2*5=5m/s

When a car moves along a straight road at a speed of 10m / s, and the acceleration is 0.2m/s2, the displacement of the car passing through in 1 min after braking is ()
A. 240mB. 250mC. 260mD. 90m.

If the time for the vehicle speed to reduce to zero is t0 = 0 − v0a = − 10 − 0.2S = 50s, then the displacement within one minute is equal to the displacement within 50s: x = v02t0 = 102 × 50m = 250m

The acceleration of the car changes with time in 0 ~ 60 seconds when the car starts to run on the straight road

If the wind resistance is not taken into account, the acceleration is constant before the maximum output power of the car is reached, and it becomes variable acceleration after the maximum power is reached, and the acceleration becomes smaller and smaller

A car moves on a straight road at an initial speed of 6m / s, and the acceleration after braking is 2m / S & sup2; How large is the displacement of the car within 2 seconds after braking? ② What is the displacement of the car within 8s after braking?