While travelling in her car Mr. Jones sees obstruction in the road It takes him 0.8 seconds to react and put his foot on the break his cars travelling at 25 m/s if when the brakes are applied the car deaccelerates How to uniform rate of 9.3 m/s squared what is the total displacement of the car The answer is 54
To find the total displacement of the car, we need to first calculate the distance traveled by the car while Mr. Jones reacts and then the stopping distance after the brakes are applied.
1. Distance traveled during reaction time:
Initial velocity (u) = 25 m/s
Time taken to react (t) = 0.8 seconds
Acceleration (a) = 0 m/s² (since no acceleration during reaction time)
Using the formula: distance = ut + (1/2)at²
Distance during reaction time = 25 x 0.8 + 0.5 x 0 x (0.8)²
Distance during reaction time = 20 meters
2. Stopping distance after brakes applied:
Acceleration (deceleration) = -9.3 m/s²
Final velocity (v) = 0 m/s (since the car stops)
Using the formula: v² = u² + 2as
0 = 25² + 2(-9.3)s
0 = 625 - 18.6s
18.6s = 625
s = 625 / 18.6
s = 33.60 meters
3. Total displacement of the car:
Total displacement = Distance during reaction time + Stopping distance
Total displacement = 20 + 33.60
Total displacement = 53.6 meters
Therefore, the total displacement of Mr. Jones' car is 54 meters.