Question

when a truck is moving at a speed of 10ms. when the driver seed charge in front, he slow and decelerated at -1.5ms^_2. Him reaction time to hit the break was 0.5sec. will the truck hit the child?

Answer 1

Initial velocity, $u = 10 m/s$

Reaction time, $t = 0.5 s$

Retardation, $a = 1.5 m/s^2$

Let x be the distance of the boy from the truck.

To avoid accident,

$ut +(uT-\frac{1}{2}aT^2) < x$

$(10 \times 0.5) + (10T-\frac{1}{2}(1.5)T^2) < x$

where T is the time after reaction time to time to reach to object.