Question

Через сколько времени после начала аварийного торможения остановится автобус ,движущийся со скоростью 12 м/с ,если тормозной путь 36м ?

Answer 1

V(0)=12 m/s; V(t)=0--->a=V(0)^2/(2*S)=12^2/(2*36)=2 m/s^2
V(t)=V(0)-a*t--->t=V(0)/a=12/2=6 s
Или
S=V(0)*t-0.5*a*t^2=12*t-0.5*2*t^2=36---->t=6 s

Answer 2

Calculating Stopping Distance of a Bus

To calculate the stopping distance of a bus after emergency braking, we can use the formula:

Stopping Distance = Initial Velocity × Reaction Time + (Initial Velocity^2 / (2 × Deceleration))

Given: - Initial velocity (u) = 12 m/s - Stopping distance = 36 m

We need to find the time it takes for the bus to stop after emergency braking.

Calculating Deceleration

First, let's calculate the deceleration using the given information.

The formula to calculate deceleration is: Deceleration = (Final Velocity^2 - Initial Velocity^2) / (2 × Stopping Distance)

Given: - Initial velocity (u) = 12 m/s - Stopping distance = 36 m - Final velocity (v) = 0 m/s (since the bus stops)

Using the formula: Deceleration = (0^2 - 12^2) / (2 × 36) Deceleration = (-144) / 72 Deceleration = -2 m/s^2

Calculating Time to Stop

Now, we can use the formula for stopping distance to find the time it takes for the bus to stop.

Stopping Distance = Initial Velocity × Reaction Time + (Initial Velocity^2 / (2 × Deceleration))

Rearranging the formula to solve for time: Time = (Final Velocity - Initial Velocity) / Deceleration

Given: - Initial velocity (u) = 12 m/s - Final velocity (v) = 0 m/s - Deceleration = -2 m/s^2

Using the formula: Time = (0 - 12) / -2 Time = 6 seconds

Conclusion

After the bus begins emergency braking, it will stop after approximately 6 seconds.