Question

Через какой промежуток времени с момента старта мотоциклист разовьёт скорость 72 км/ч, двигаясь с постоянным ускорением 5 м/с?

Answer 1

Дано:
$v _{0} = 0$ м\с

$v= 72$ км\ч

$a = 5$ м\$c ^{2}$

Найти:
t=?

Решение:
$V= V _{0} + at$

Но так как начальная скорость у нас равна 0,то 

$V= at$ 

=>

$t= \frac{v}{a}$

$t= \frac{20}{5} = 4$ с

Ответ: 4 с

Answer 2

Calculating Time to Reach 72 km/h with Constant Acceleration

To calculate the time it takes for a motorcyclist to reach a speed of 72 km/h with a constant acceleration of 5 m/s^2, we can use the following steps:

1. Convert the speed from km/h to m/s. 2. Use the formula for calculating time with constant acceleration.

Let's proceed with the calculations.

Conversion of Speed from km/h to m/s

To convert 72 km/h to m/s, we use the following conversion factor: 1 km/h = 0.277778 m/s

So, 72 km/h = 20 m/s.

Calculating Time with Constant Acceleration

We can use the following kinematic equation to calculate the time it takes to reach a certain speed with constant acceleration: \[ v = u + at \] Where: - \( v \) = final velocity (20 m/s) - \( u \) = initial velocity (0 m/s, as the motorcyclist starts from rest) - \( a \) = acceleration (5 m/s^2) - \( t \) = time

We can rearrange the equation to solve for \( t \): \[ t = \frac{v - u}{a} \]

Substituting the values: \[ t = \frac{20 - 0}{5} = 4 \, \text{s} \]

So, the motorcyclist will reach a speed of 72 km/h (20 m/s) in 4 seconds with a constant acceleration of 5 m/s^2.

[[SOURCE #3]]