Question

A car accelerates uniformly from 18 km/hr to 90 km/hr in 10 seconds
a) Calculate the accelaration (a)
b) and distance covered by car

Answer 1

Given : A car accelerates uniformly from 18 km/hr to 90 km/hr in 10 seconds

a) Calculate the acceleration

b) and distance covered by car

Solution : According to the given question, here we are provided that the initial velocity of the car is 18km/h and the final velocity is 90km/h and the time taken is 10sec

So, now let's convert km/h into m/sec

General Formula : 1 km/h = 5/18 m/sec

Initial Velocity = 18km/h = 5m/sec

Final Velocity = 90km/h = 25m/sec

a) Finding Acceleration

For finding acceleration we need to apply the first equation of motion

★ First Eq. of Motion : v = u + at ★

Putting all the given values in the formula

• 25 = 5 + a(10)

• 25 = 5 + 10a

• 25 - 5 = 10a

• 10a = 20

• a = 2

Henceforth, acceleration is 2 m/sec.

b) Finding Distance

For achieving distance covered we need to apply the second equation of motion

★ Second Eq. of Motion = S = ut + ½at² ★

Putting all the required values inc. acceleration in this equation we get

• S = 5(10) + ½ × 2(10)²

• S = 50 + 100

• S = 150

Therefore, distance covered is 150 metres.