Answer:
![a=-2.45\ m/s^2](https://img.qammunity.org/2021/formulas/physics/high-school/l60rs9l7i3e9srunwg8hxbwl1edh553k2o.png)
Step-by-step explanation:
An object is traveling at constant acceleration if its changes in speed are constant at the same intervals of time.
The acceleration can be calculated as follows:
![\displaystyle a=(v_f-v_o)/(t)](https://img.qammunity.org/2021/formulas/physics/middle-school/gnk7m72pgsvouvn3ei1776clul5czi0j8u.png)
Where vo is the initial speed, vf the final speed and t is the time.
The acceleration and the distance x are related through the following equation:
![v_f^2=v_o^2+2.a.x](https://img.qammunity.org/2021/formulas/physics/high-school/hdf06ocp605nadcbipeal2ulfcp4vnqnnc.png)
The car has an initial speed of vo=7 m/s when the driver stops the car (vf=0) after traveling x=10 m.
The acceleration can be calculated by solving the last equation for a:
![\displaystyle a=(v_f^2-v_o^2)/(2x)](https://img.qammunity.org/2021/formulas/physics/high-school/mwzlnfparvbnk7b1wp368lyhl3593gwp2u.png)
![\displaystyle a=(0-7^2)/(2*10)](https://img.qammunity.org/2021/formulas/physics/high-school/3wmscy2xtlwm5knexabbdexf56wk1svqay.png)
![\displaystyle a=(-49)/(20)](https://img.qammunity.org/2021/formulas/physics/high-school/qm131jajskbny5xn2nxpiv7fvnhdz1satd.png)
![\boxed{a=-2.45\ m/s^2}](https://img.qammunity.org/2021/formulas/physics/high-school/qhuvdlm2z3mkaqn441bhjshlhqr3bsz4v4.png)