The car covered a distance of 20 km at an average speed of 80 km / h. Acceleration and braking took 2 minutes.

| September 18, 2021 | education

The car covered a distance of 20 km at an average speed of 80 km / h. Acceleration and braking took 2 minutes. The rest of the time the car was moving at a constant speed. determine this speed

1). From the fact that the car traveled at an average speed of v = 80 km / h the distance S = 20 km, you can find the time that the car was on the way using the formula: t = S: v. Let’s substitute the values ​​of physical quantities in the formula: t = 20 km: 80 km / h; t = 0.25 h = 15 min.
2). Since it took 2 minutes to accelerate and decelerate, we will determine the rest of the time that the car was moving at a constant speed by subtracting: 15 minutes – 2 minutes = 13 minutes = 13/60 hours. To find this speed of uniform motion, we use the formula: v = S: t; that is, v = 20 km: 13/60 hours = 92.3 km / h. Or 20,000 m: (13 • 60) s = 25.6 m / s.
Answer: the speed of uniform movement of the vehicle is v = 92.3 km / h = 25.6 m / s.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.