1.2.19 | revision #13333 | Savchenko Solutions

Statement

1.2.19. The speedometer scale is $15\text{ cm}$ long and measures the vehicle speed from zero to $150~\mathrm{\frac{km}{h}}$ . Find the speed of the speedometer indicator if the car is moving at an acceleration of $2~\mathrm{\frac{m}{s^2}}$ .

For problem $1.2.19$ — For problem $$1.2.19$$

Solution

Equation for equal accelerated motion

$150 \text{ km/h}=0 \text{ km/h}+at_n$

Acceleration time from zero to full speed

$t_n=20.83 \text{ s}$

During this time, the speedometer arrow will travel the distance

$15 \text{ cm}=ut_n$

making the speed equal to

$u=0.72 \text{ cm/s}$

Answer

$v = 0.72 \text{ cm/s}$