Question

a car travels a distance hundred metre with a constant acceleration and average velocity of 20 metre per second the final velocity acquired by the car is 25 m per second find the initial velocity and acceleration of the car

Answer 1

Average velocity V Avg = (v+u)/2 ⇒ 20 = (25+u)/2 ⇒ u = 40 -25 ⇒ u = 15 m/s
a=(v2 – u2)/2s ⇒ a=(252 – 152)/(2 ⨯ 100) ⇒a= (625 -225)/200 ⇒ a = 2 m/s2

Answer 2

Answer:

Answer ⇒ Option (c). The minimum stopping distance is same for both the cars.

Explanation ⇒  Let us take an help of the mathematical expression to derive our result.

We know that when car will be stopped then the Force of Friction acting will be the Limiting Friction.

∴ f = μmg

Now, ma =  μmg

⇒ a =  μg

Since, the acceleration is independent of the mass thus the minimum stopping distance will also be independent of the mass as they have the same initial speed. [Taking help of the Second Equation of motion.]

∴ Option (c). is correct answer.