Answer:
a)
![A=5m/s^2](https://img.qammunity.org/2022/formulas/physics/high-school/gw4hbzozpzngo8wkebhg38dghcdvo864t1.png)
b)
![V=25m/s](https://img.qammunity.org/2022/formulas/physics/high-school/xx3sogre70u5yrdzojnrcimhq2gzk97ahd.png)
Step-by-step explanation:
From the question we are told that:
Velocity
![v=90km/h=25m/s](https://img.qammunity.org/2022/formulas/physics/high-school/1q5nccfcy5vmen4pqf5b8fj5fppc3p04e1.png)
Time
![t=5.0s](https://img.qammunity.org/2022/formulas/physics/high-school/t74hj1i3u8nlz8imia0x08w8f5tcluxp5t.png)
a)
Generally From Newton's motion equation for Average acceleration is mathematically given by
![A=(V-U)/(t)](https://img.qammunity.org/2022/formulas/physics/high-school/y7yl58yb496urlr59boe8ok1lefyxtpncb.png)
Since its from Rest Therefore
![U=0](https://img.qammunity.org/2022/formulas/physics/high-school/9ge78km48vvjmutmptsov9e9g7a6s3ui9y.png)
![A=(25m/s-0)/(5s)](https://img.qammunity.org/2022/formulas/physics/high-school/3znauug6ri0m4jjk873s3e4vhi2nezxi12.png)
![A=5m/s^2](https://img.qammunity.org/2022/formulas/physics/high-school/gw4hbzozpzngo8wkebhg38dghcdvo864t1.png)
b)
Generally the equation for Average Velocity is mathematically given by
![V=u+at](https://img.qammunity.org/2022/formulas/physics/high-school/8h79h9srjw7pvjuofa6g7rt7atcd5l9hug.png)
![AT t=1.0s\\\\V=0+5(1)](https://img.qammunity.org/2022/formulas/physics/high-school/p85j0wgvael0ltwrxkjlxp8v5ibuc34hnu.png)
![V=5m/s](https://img.qammunity.org/2022/formulas/physics/high-school/11rqkgu5zbpxsxuledaichmdrxxetwpi46.png)
![AT t=2.0s\\\\V=0+5(2)](https://img.qammunity.org/2022/formulas/physics/high-school/otkiy3xkls52ue6avlc5vgm8ogkag4pewz.png)
![V=10m/s](https://img.qammunity.org/2022/formulas/physics/college/2mn4u6y3rleibdrbq6hee91hs8vgyv81z2.png)
![AT t=5.0s\\\\V=0+5(5)](https://img.qammunity.org/2022/formulas/physics/high-school/milcjvyi9kpuio1bo8ur0b1pia3768rmji.png)
![V=25m/s](https://img.qammunity.org/2022/formulas/physics/high-school/xx3sogre70u5yrdzojnrcimhq2gzk97ahd.png)