Answer:
The velocity of the student and skateboard together

Step-by-step explanation:
Given:
Mass of student

Mass of skateboard

Distance between student and skateboard

Acceleration of student

Finding velocity
of the student before jumping on skateboard
Using equation of motion

here
represents the initial velocity of the student which is
as he starts from rest.
So,


Taking square root both sides:

∴

Finding velocity
of student and skateboard.
Using law of conservation of momentum.

Where
is initial velocity of skateboard which is
as it is at rest.
Plugging in values.


Dividing both sides by


∴

The velocity of the student and skateboard together
