Question

Um caminhão viaja pela estrada com velocidade de 70km/h. Diante de um obstáculo ele é freado e para cerca de 360 segundos depois. Qual foi a aceleração media?

Answer 1

Answer:
`-0.054 m/s^(2)`

Step-by-step explanation:

The question in english is written below:

A truck travels along the road at a speed of 70 km/h. It encounters an obstacle and brakes for about 360 seconds until it stops. What is the average acceleration of the truck?

Average acceleration
`a_(ave)` is the variation of velocity
`\Delta V` over a specified period of time
`\Delta t`:

`a_(ave)=(\Delta V)/(\Delta t)}`

Where:

`\Delta V=V_(f)-V_(o)`

`V_(o)=70 (km)/(h)(1000 m)/(1 km) (1 h)/(3600 s)=19.44 m/s` is the initial velocity

`V_(f)=0 m/s` the final velocity

`\Delta t=360 s`

Then:

`a_(ave)=(V_(f)-V_(o))/(\Delta t)}`

`a_(ave)=(0 m/s-19.44 m/s)/(360 s)}`

Finally:

`a_(ave)=-0.054 m/s^(2)` Note the negative sign in the acceleration indicates the truck was decreasing its velocity until it stopped.