Question

Понятия не имею как решить.. если напишете объяснение, буду очень благодарен. Даю 50 баллов Автомашина, скорость которой равна 14 м/с, тормозит и через 3 секунд останавливается на красный свет светофора. Чему равна проекция ускорения на направление движения автомашины? Результат округлите до сотых.

Answer 1

Ответ: -4,7м/с²

Объяснение:

Дано:

Vo=14м/с

V=0м/с

t=3c

=========

а-?

V=Vo+at

Vo+at=0

Vo=-at

a=-Vo/t=-14/3=-4,7м/с²

Answer 2

Calculation of the Projection of Acceleration

To calculate the projection of acceleration on the direction of motion of the car, we need to know the initial velocity, final velocity, and the time taken to come to a stop.

Given: - Initial velocity (u) = 14 m/s - Time taken to stop (t) = 3 seconds

To find the final velocity (v), we can use the formula:

v = u + at

where: - v is the final velocity - u is the initial velocity - a is the acceleration - t is the time taken

Since the car comes to a stop, the final velocity (v) is 0 m/s. Therefore, we can rewrite the formula as:

0 = 14 + a * 3

Simplifying the equation:

a * 3 = -14

a = -14 / 3

The negative sign indicates that the acceleration is in the opposite direction of motion. Now, we can calculate the projection of acceleration (a') on the direction of motion by multiplying the acceleration (a) by the cosine of the angle between the acceleration vector and the direction of motion.

Since the acceleration is opposite to the direction of motion, the angle between them is 180 degrees. Therefore, the cosine of 180 degrees is -1.

a' = a * cos(180) = -14 / 3 * -1 = 14 / 3 ≈ 4.67 m/s²

Therefore, the projection of acceleration on the direction of motion of the car is approximately 4.67 m/s².

Please note that the sources provided do not contain relevant information for this specific calculation.