A car changes its speed from 0 to 20 m/s in 4 seconds. What is the acceleration?

5 m/s2

Explanation:

Acceleration =Change in velocity/ time

Or

a= v2 - v1/ t

a = 20- 0 /4

a = 20÷ 4

a= 5meters per seconds square

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s