Question

a driver of car traveling at 72 km/hr applies brakes and accelerates uniformly in the opposite direction. the car stops in 6 second. then the acceleration of the car is​

Answer 1

Answer:

is the accelaratin -12?

Explanation:u can do by the equation of (v=u+a7) or (a=v-u/t) tbh both are same

Answer 2

Given:

• Initial velocity(u) = 72km/h = 5/18 × 72 = 20m/s.
• Final velocity(v) = 0m/s
• Time(t) = 6s
• Acceleration(a) = ???

Acceleration = $\tt{\frac{Change\space in\space velocity}{Time}}$

Acceleration = $\tt{\frac{v-u}{t}}$

Acceleration = $\sf\frac{0-20}{6}$

Acceleration = $\sf\frac{-20}{6}$

Acceleration = $\sf{-0.33m/s^2}$

Since, the acceleration is negative, so, retardation takes place.

Hence, the acceleration or redardation of the car is -0.33m/s

Additional Information:

When an object is increasing its speed it is said to have positive acceleration and when an object is slowing down it has negative acceleration also known as retardation. Acceleration has both magnitude and direction and is a vector quantity.