Question

A car travelling at constant speed on a straight level road accelerate so that its speed is now doubled. By what factor will the car's kinetic energy change? explain by using physics principles? ​

Answer 1

Answer:

By a factor of 4

Explanation:

We know that, the kinetic energy

$ke= \frac{1 }{2} m{v}^{2}$

and we also know that the acceleration causes the speed's value to be doubled

Hence, v becomes 2v

When 2v is squared, it becomes 4v^2. After substituting this value in the equation above and comparing it,

We can conclude that the Kinetic Energy has increased by a fa tor of 4.

Hope it helps you!

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.