Question

A car driver traveling 40 m/s slows down to a speed of 20 m/s in 10 seconds. What is the car’s acceleration?

Answer 1

the answer to this question is

-2 per second

Answer 2

The equation we use is to determine the acceleration of the car, it is a Uniformly Varied Rectilinear Motion (MRUV) is:

`\boxed{\sf{a=(V_(f)-V_(o))/(t)}} \ \ \ \ \ \sf{\longmapsto \ \ \ \ \ Where \ \ \ \ \begin{cases}\sf{V_(f) = Final \ velocity} \\ \sf{V_(o)=Initial \ velocity} \\ \sf{a=Acceleration} \\ \sf{t=Time} \end{cases}}`

We extract the data of the problem:

• 
  `\sf{V_(f)=20 \ m/s}`

• 
  `\sf{V_(o)=40 \ m/s}`

• 
  `\sf{t=10 \ s}`

We plug these values into the scalar equation above.

`\sf{a=(V_(f)-V_(o))/(t)}`

`\sf{a=(20 \ m/s-40m/s)/(10 \ s) }`

`\sf{a=(-20 \ m/s)/(10 \ s) }`

`\boxed{\boxed{\boldsymbol{\sf{a=-2 \ m/s^(2) }}}}`

Rpta: The acceleration of the car was -2 m/s^2.