Calculate the average velocity of the car for the time interval t=0 to t1 = 1.91s?

A Honda Civic travels in a straight line along a road. Its distance x from a stop sign is given as a function of time t by the equation x(t)= α β t3, where α = 1.43m/s2 and β =

1.) Calculate the average velocity of the car for the time interval t=0 to t1 = 1.91s.

2.) Calculate the average velocity of the car for the time interval t=0 to t2 = 3.93s.

3.) Calculate the average velocity of the car for the time interval t1 = 1.91s to t2 = 3.93s.

Could someone show me how to do this step by step? Completely lost

To determine the average velocity, use the following equation.
V ave = * (vi + vf)

x = 1.43 * t^2 - 4.5 * 10^-2 * t^3
To determine the equation for velocity versus time, take the first derivative of the equation above.

vf = vi + 2.86 * t - 0.135 * t^2
For the first 1.91 seconds, vi is 0 m/s.
vf = 2.86 * 1.91 - 0.135 * 1.91^2 = 4.9701065 m/s
V ave = * 4.9701065 = 2.48503525 m/s

For the second time period, vi is 0 and t is 3.93 seconds

vf = 2.86 * 3.93 - 0.135 * 3.93^2 = 9.1547385 m/s
V ave = * 9.1547385 = 4.57736925 m/s

For the third time period, time is not 3.93 seconds. To determine the time, subtract 1.91 seconds from 3.93, t = 2.02 seconds. Vi is 4.9701065 m/s.

vf = 4.9701065 + 2.86 * 2.02 - 0.135 * 2.02^2 = 10.1964525 m/s

V ave = * (4.57736925 + 10.1964525) = 7.386910875 m/s

I suggest that you check my calculations to determine if I have made any mistakes!

X(t) = position vector. Change in position over time is average velocity

1) [x(1.91) - x(0)] / [1.91 - 0]
2) [x(3.93) - x(0)] / [3.93 - 0]
3) [x(3.93) - x(1.91) / [3.93 - 1.91]

X(t) = α β where α = 1.43 and β =

= displacement / time, where displacement = x(tii) - x(ti) in a time interval (tii - ti)

1.) the average velocity of the car for the time interval t=0 to ti = 1.91s.

x(0) = 0
x(1.91) = α β = 1.43(3.6481) - (0.045)(6.967871) = 5.216783 - 0.313554195 = 4.903228805

=> = 4.903228805 / (1.91 - 0) = 2.5671355 m/s

2.) Calculate the average velocity of the car for the time interval t=0 to t2 = 3.93s.

x(0) = 0
x(3.93) = α β = 1.43(15.4449) - (0.045)(60.698457) = 22.086207 - 2.731430565 = 19.354776435

=> = 19.354776435 / (3.93 - 0) = 4.9248795 m/s

3.) the average velocity of the car for the time interval t1 = 1.91s to t2 = 3.93s

x(1.91) =4.903228805 m
x(3.93) = α β = 1.43(15.4449) - (0.045)(60.698457) = 22.086207 - 2.731430565 = 19.354776435 m

=> = [19.354776435 - 4.903228805] / (3.93 - 1.91) = 14.45154763 / 2.02 m/s = 7.1542315 m/s

hope this helps