Question

A car accelerates uniformly from 18 km h -¹ to 36 km h -¹ in 5 s. Calculate acceleration Distance covered

Answer 1

Answer:

s=37.5m a= 1m/s^2

Explanation:

u=18km/h

  =18×1000m / (60×60s) =5m/s,

v=36km/h = 10m/s,

t=5s

a = (v−u)/t = (10−5) / 5

   =1m/s^2

From s=ut + 1/2at^2,

s=5×5+1/2×1×5^2

  =37.5m

Answer 2

GiveN :

• Initial velocity (u) = 18 km/h
• Final velocity (v) 36 km/h
• Time interval (t) = 5 s

To FinD :

• Acceleration of car
• Distance travelled by car

SolutioN :

Convert Time into m/s from km/h, by multiplying with 5/18

• Initial velocity = 18 * (5/18) = 5 m/s
• Final velocity = 36 * (5/18) = 10 m/s

Use 1st equation of motion :

⇒v = u + at

⇒10 = 5 + a * 5

⇒5a = 10 - 5

⇒5a = 5

⇒a = 5/5

⇒a = 1

∴ Acceleration of car is 1 m/s²

_______________________

Now, to calculate distance travelled by car :

Use 3rd equation of motion :

⇒v² - u² = 2as

⇒10² - 5² = 2 * 1 * s

⇒2s = 100 - 25

⇒2s = 75

⇒s = 75/2

⇒s = 37.5

∴ Distance travelled by car is 37.5 m.