Question

A car acquire a velocity of 72 km per hour in 10 second starting from rest. Find

(1) the acceleration,
(2) the average velocity, and
(3) the distance travelled in this time.

Answer 1

We have the following information,
Initial velocity, (u) = 0 m/s
Final velocity
`(v)` = 72 km/hr
= `"72(1000)"/3600` m/s
= 20 m/s
Time taken , (t) = (10) s
(i) So acceleration,
`a = (v-u)/t`
Put the values in the above equation to get the value of acceleration
`a = (20-0)/10`
 = 2 `"m/s"^2`
(ii) we have to find the average velocity. we will use the following relation,
Average velocity = `"Initial velocity + Final velocity"/2`
So , Average velocity = `(v+u)/2`
Therefore putting the value in the above to get the avearge velocity , 
Average velocity = `(20+0)/2`  m/s
= 10 m/s
(iii) We have to calculate the distance travelled. We will use the relation,
Distance travelled = (Average velocity) (Time)
So distance travelled is,
= (10)(10) m
= 100 m