Question

Ann is driving down a street at 63 km/h.

Suddenly a child runs into the street.
If it takes Ann 0.777 s to react and apply
the brakes, how far will she have moved before
she begins to slow down?
Answer in units of m

Answer 1

s = 13.6 m

Step-by-step explanation:

Ann is driving at a constant speed. Hence, the formula of uniform motion shall be used here. The formula for the distance traveled during uniform speed motion is given as follows:

s = vt

where,

s = distance covered by the car before it begins to slow down= ?

v = uniform speed of car = (63 km/h)(1000 m/ 1 km)(1 h/3600 s) = 17.5 m/s

t = time to react before applying brakes = 0.777 s

Therefore, using the values in the equation, we get:

s = (17.5 m/s)(0.777 s)

s = 13.6 m