Question

nd: A car at rest acclerates Uniformly to a speed of 90 km per hour in 30 s. How much distance is covered by the car.
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Answer 1

Answer:

375 m

Given

initial velocity of the car = 0 m/s.

v = 90 km/h = 90 × 5/18 m/s = 25 m/s.

t = 30 second.

To Find

Distance covered by the car in this period.

Formulas :-

a = $\dfrac{v\:-\:u}{t}$

v² - u² = 2as.

Calculations

Let us first calculate acceleration using above formula :-

a = $\dfrac{v\:-\:u}{t}$

=> a = $\dfrac{25\:-\:0}{30}$

=> a = $\dfrac{5}{6}$

Now,using second formula,we can find s.

v² - u² = 2as

=> (25)² - 0 = 2 × $\dfrac{5}{6}$ × s

=> 625 = $\dfrac{5}{3}$ × s

=> s = 125 × 3

=> s = 375 m

Answer 2

Answer

Distance travelled by the car is 375 m

Given

A car at rest accelerates Uniformly to a speed of 90 km per hour in 30 s

To Find

Distance covered by the car

Concept Used

As the acceleration of the car is constant throughout the motion , so we need to apply equation's of kinematics

Solution

Acceleration , a = ? m/s²

Initial velocity , u = 0 m/s

Since starts from rest

Final velocity , v = 90 km/h = 25 m/s

Distance , s = ? m

Apply 1st equation of motion ,

⇒ v = u + at

⇒ 25 = 0 + a(30)

⇒ 25 = 30a

⇒ a = 0.834 m/s²

So , Acceleration = 0.834 m/s²

Apply 3rd equation of motion ,

⇒ v² - u² = 2as

⇒ (25)² - (0)² = 2(0.834)s

⇒ 625 = 1.67s

⇒ s = 375 m

So , Distance travelled by the car is 375 m