a car is moving down a street at 55km/h.A child suddenly runs into the street. If it takes a driver 0.75s to react and apply the brakes, how many meters will the car have moved before it begins to slow down?
11.46m
To find out how many meters the car will have moved before it begins to slow down, we can use the equation:
Distance = Speed x Time
Given:
Speed of the car = 55 km/h
Time taken by the driver to react = 0.75 s
First, let's convert the speed from kilometers per hour (km/h) to meters per second (m/s). We can do this by multiplying the speed by a conversion factor of 1000/3600:
Speed (in m/s) = (55 km/h) x (1000 m/1 km) x (1 h/3600 s)
= (55 x 1000)/(3600)
= 55000/3600
= 15.28 m/s (rounded to two decimal places)
Now, we need to calculate the distance the car will have moved during the driver's reaction time.
Distance = Speed x Time
Distance = 15.28 m/s x 0.75 s
Distance = 11.46 m (rounded to two decimal places)
Therefore, the car will have moved approximately 11.46 meters before the driver begins to slow down.
To find how many meters the car will have moved before it begins to slow down, we need to consider the distance covered during the reaction time.
1. Convert the speed of the car from kilometers per hour to meters per second:
- 55 km/h = (55 * 1000) m / (60 * 60) s
- = 55000 m / 3600 s
- ≈ 15.28 m/s
2. Calculate the distance covered during the reaction time of 0.75 seconds:
- Distance = Speed * Time
- Distance = 15.28 m/s * 0.75 s
- ≈ 11.46 meters
Therefore, the car will have moved approximately 11.46 meters before the driver reacts and applies the brakes.
55 km/h = 55000m/3600 s = 15.28 m/s.
Multiply that by the reaction time (0.75 s) for the number of meters travelled before slowing down.