Ann is driving down a street at 59 km/h.
Suddenly a child runs into the street.
If it takes Ann 0.774 s to react and apply
the brakes, how far will she have moved before
she begins to slow down?
Answer in units of m
Emily takes a trip, driving with a constant velocity of 81.5 km/h to the north except for a 22 min rest stop. If Emily's average velocity is 72.8 km/h to the north, how long does the trip take?
To find the distance Ann will have moved before she begins to slow down, we can use the formula:
Distance = (Initial velocity × Reaction time) + (0.5 × Acceleration × Reaction time^2)
Given:
Initial velocity (v) = 59 km/h = (59 × 1000) / 3600 m/s = 16.39 m/s
Reaction time (t) = 0.774 s
Acceleration (a) = 0 m/s^2 (since she starts slowing down)
Using the formula, let's calculate the distance:
Distance = (16.39 × 0.774) + (0.5 × 0 × 0.774^2)
= 12.69 + 0
= 12.69 m
Therefore, Ann will have moved approximately 12.69 meters before she begins to slow down.
To find the distance Ann will have moved before she begins to slow down, we need to calculate the distance traveled in the time it takes her to react and apply the brakes.
First, let's convert Ann's speed from km/h to m/s.
1 km/h is equivalent to 1000 m/3600 s,
so Ann's speed is 59 km/h * (1000 m/3600 s) = 16.39 m/s (rounded to two decimal places).
Now we can calculate the distance traveled before she begins to slow down. We'll use the formula:
Distance = Speed * Time
Given that the time it takes Ann to react and apply the brakes is 0.774 s, we can substitute the values into the formula:
Distance = 16.39 m/s * 0.774 s
Calculating the result:
Distance = 12.67 m (rounded to two decimal places)
Therefore, Ann will have moved approximately 12.67 meters before she begins to slow down.
distance= velocity*time=59km/hr*.774 seconds.
well, some unit conversion is in order.
distance= 59km(1000m/km)*1/hr * 1hr/3600s*.774 s
that does it.