Question

II. Solve the following numerical:
⦁ A car starts from rest and attains a velocity of 18 km/h in 2 s. Find its acceleration in SI units.




⦁ A driver decreases the speed of a car from 25 m/s to 10 m/s in 5 seconds. Find the acceleration of the car.
⦁ A bus decreases its speed from 80 km/h to 60 km/h in 5 minutes (1/12 hour). Find the acceleration of the bus in km/h.

Answer 1

Explanation:

1)a=velocity/time

we should convert 18 km/h into m/sec for this we should multiply with 5/18

v=18×5/18

=5m/s

a=5/2m/s^2

2)a=change in velocity/time

change in velocity = 10-25=-15m/s

a=-15/5

a=-3m/s^2 it is decelerating

3)a=change in velocity/time

change in velocity =60-80=-20km/h

a=-20/(1/12)

a=-240km/h

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