Question

A car initially traveling at 20 kilometers per hour takes 10 seconds to speed up to 70 km/hour. At what rate is it changing speed?

Answer 1

• Initial velocity=u=20km/h
• Final velocity=v=70km/h
• Time=10s=t

Convert speeds to m/s

`\\ \rm\longmapsto u=20*(5)/(18)=5.05m/s`

`\\ \rm\longmapsto v=70* (5)/(18)=19.4m/s`

`\boxed{\sf Acceleration=(v-u)/(t)}`

`\\ \rm\longmapsto Acceleration=(19.4-5.05)/(10)`

`\\ \rm\longmapsto Acceleration=(14.3)/(10)`

`\\ \rm\longmapsto Acceleration=143m/s^2`