Question

A motor car is travelling at 36 kmhr -1 . After 10 s, the velocity becomes 54 kmhr -1 . Assuming the
velocity change took place at uniform rate, find the acceleration.

Answer 1

Answer:

0.5m/s²

Explanation:

given,

initial velocity (u) = 36km/h= 36×5/18=10m/s

final velocity (v)= 54km/h= 54×5/18= 15m/s

time taken to achieve u to v= 10 s

since, v = u+at

=> 15= 10+a×10

=>. 15-10= 10a

=> a= 0.5 m/s²

acceleration= 0.5m/s²

Answer 2

Given:-

• Initial Velocity (u) of the car = 30 km/hr
• Final velocity (v) of the car = 60 km/hr
• Time taken (t) by the car = 10 seconds

To find:-

• Find is the acceleration of the car ?

Solutions:-

We have given that,

The initial Velocity and final velocity of the car is 36 km/hr and 54 km/hr.

Convert km/hr into m/s:-

=> u = 36 × 5/18

=> u = 2 × 5

=> u = 10m/s

Convert km/hr into m/s:-

=> v = 54 × 5/18

=> v = 3 × 5

=> v = 15m/s

Acceleration = (final velocity - initial velocity)/time taken

According to question:-

=> A = (15 - 10)/10

=> A = 5/10

=> A = 0.5m/s².

Hence, the acceleration of the car is 0.5 m/s².

Some Important:-

Speed, Time and Distance:

• Speed = Distance/Time
• Time = Distance/speed
• Distance = Speed × Time

km/hr to m/sec conversion:

• x km/hr = x × 5/18 m/sec.

m/sec to km/hr conversion:

• x m/sec = x × 18/5 km/hr.