Question

What is the acceleration of a vehicle that changes its velocity from 100 km/h to a dead stop in 30 s ? Answer in units of m/s 2 .

Answer 1

The acceleration of a vehicle slowing down from 100 km/h to a dead stop in 30 seconds is -0.926 m/s², indicating deceleration.

Step-by-step explanation:

The acceleration of a vehicle that changes its velocity from 100 km/h to a dead stop in 30 s can be calculated using the formula for average acceleration, which is a = Δv/Δt. First, we convert the initial velocity from kilometers per hour to meters per second: 100 km/h = (100 * 1000 m) / (3600 s) = 27.78 m/s. Since a dead stop means the final velocity is 0 m/s, we have Δv = 0 m/s - 27.78 m/s = -27.78 m/s (negative because the velocity is decreasing). Now, the average acceleration is a = Δv/Δt = -27.78 m/s / 30 s = -0.926 m/s², where the negative sign indicates deceleration.

Answer 2

a =
`-(25)/(27)` m/s²

Step-by-step explanation:

Acceleration (a) = (final velocity - initial velocity) ÷ (final time - initial time) =
`(v_(f) - v_(i) )/(t_(f) - t_(i) )`

Converting the speed from km/h to m/s;

100 km = 100000m

1hr = 3600s

∴ 100km/hr ⇄
`(100000 m)/(3600 s)` =
`(250)/(9) m/s`

Acceleration =
`(0 - 250/9)/(30)` =
`-(250)/(9 * 30) = -(25)/(27)` m/s²

i.e deceleration =
`(25)/(27)` m/s²