Given the initial speed and time elapsed by the car, the negative acceleration that brings the car to a stop at the red light is -5.56m/s².
What is the acceleration of the car?
Newton's first equation of motions states that;
v = u + at
Where v is final velocity, u is initial velocity, a is acceleration and t is time.
Given the data in the question;
- Since the car is stopping, final velocity v = 0
- Initial velocity u = 80 km/h
- Time elapsed t = 4s
- Acceleration = ?
First, convert the unit of the initial velocity from kilometer per hour to meter per seconds
Initial velocity = 80 km/h = ( 80 × 5/18 )m/s = 2.2222 m/s
Now, plug these values into the equation above and solve for a.
v = u + at
0 = 22.2222m/s + ( a × 4s )
a × 4s = -22.2222m/s
a = 22.2222m/s ÷ 4
a = -5.56m/s²
Negative sign shows that the car is slowing down.
Given the initial speed and time elapsed by the car, the negative acceleration that brings the car to a stop at the red light is -5.56m/s².
Learn more about Equations of Motion here: brainly.com/question/18486505
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