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Class 11
Physics
Motion in a straight Line
a car moving along a straight highway with a speed...

Question:
A car moving along a straight highway with a speed of 126 km h^–1 is brought to a stop within a distance of 200 m. What is the retardation of the car (assumed uniform), and how long does it take for the car to stop?

Answer:

Initial velocity of the car, u = 126 km/h = 35 m/s

Final velocity of the car, v = 0

Distance covered by the car before coming to rest, s = 200 m

Retardation produced in the car = a

From third equation of motion, a can be calculated as:

v² - u² = 2as

(0)² - (35)² = 2 x a x 200

a = - (35 x 35) / (2 x 200)

a = -3.06 m/s2

From first equation of motion, time (t) taken by the car to stop can be obtained as:

v = u + at

t = v - u / a

= -35 / -3.06 = 11.44 s

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Question:
A car moving along a straight highway with a speed of 126 km h^–1 is brought to a stop within a distance of 200 m. What is the retardation of the car (assumed uniform), and how long does it take for the car to stop?

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Question: A car moving along a straight highway with a speed of 126 km h–1 is brought to a stop within a distance of 200 m. What is the retardation of the car (assumed uniform), and how long does it take for the car to stop?

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Question:
A car moving along a straight highway with a speed of 126 km h^–1 is brought to a stop within a distance of 200 m. What is the retardation of the car (assumed uniform), and how long does it take for the car to stop?