Question

If a car changes its velocity from 32 km/hr to 54 km/hr in 8.0 seconds, what is its acceleration?

216 km/hr/sec
2.8 km/hr/sec
-216 km/hr/sec
-2.8 km/hr/sec

Answer 1

Use the equation vf = vi + at to determine the acceleration:

54 = 32 + (a)(8)
22 = 8a
a = 2.75 km/h/s

B

Answer 2

Answer: Option (b) is the correct answer.

Step-by-step explanation:

The given data is as follows.

Initial velocity,
`v_(i)` = 32 km/hr, Final velocity,
`v_(f)` = 54 km/h

Time (t) = 8.0 seconds.

Calculate the acceleration, using the formula as follows.

`v_(f)` =
`v_(i)` + a × t

54 km/hr = 32 km/hr + a × 8 sec

(54 - 32) km/hr = a × 8 sec

22 km/hr = a × 8 sec

or, a =
`(22 km/hr)/(8 sec)`

= 2.75 km/hr/sec

= 2.8 km/hr/sec (approx)

Thus, we can conclude that acceleration of the car is 2.8 km/hr/sec (approx).