Question

A car was traveling north on straight road on at 50 kilometers per hour. It slowed to 20 kilometers per hour 30 meters before a stop sign. At the stop sign, the car fully stopped. As the car traveled toward the stop sign it’s -answer

Answer 1

To determine the duration of a car's journey involving acceleration and deceleration, we apply kinematic equations that consider initial and final velocities, acceleration rates, distances, and time taken in each phase of motion.

Step-by-step explanation:

The scenario involves understanding kinematic equations and the concepts of acceleration and deceleration. To solve problems like these, one must apply the basic equations of motion for uniformly accelerated rectilinear motion.

Example Calculation

For a car accelerating from rest at a stop sign, we use the equation vf = vi + at, where vf is the final velocity, vi is the initial velocity, a is the acceleration, and t is the time. Conversely, for deceleration, the same formula applies but with negative acceleration. When given the distance to a second stop sign, we can incorporate the equation s = vit + 0.5at², where s is the distance traveled, to determine the time until the car stops again.

Bus Example

For a bus that starts from rest and accelerates at 2 m/s² to a speed of 20 m/s, then continues at constant speed before decelerating uniformly to rest in 5 seconds, we must calculate each phase separately and sum the times.