The initial velocity of go-kart is 2.5 m/s.
<u>Explanation:</u>
Here, the uniform acceleration of go-kart is given as 0.5 m/s². Also the time required by it to stop is also given as 5 s. As acceleration is the measure of change in velocity per unit time.
In this case, the velocity should be changed from a value to zero to come to rest. So the initial velocity will be positive value and final velocity is zero.
As we know the values of acceleration, final velocity and time, the initial velocity can be easily determined as follows.

Since, final velocity is zero, acceleration is 0.5 m/s² and time is 5 s, then,

Initial velocity = 0.5 × 5 = 2.5 m/s.
So the initial velocity of go-kart is 2.5 m/s.
Momentum = mass • velocity
v= 17.5/2.5
= 7 m/s
Height of baby carriage from ground = 21m
Mass of carriage with baby = 1.5 kg
The carriage has potential energy by virtue of its height.
Potential energy = mgh = 1.5×10×21 = 315 J
Hence, potential energy of the carriage is 315 Joule.
It would be Thermal Radiation
That can be considered alive.