Question

Define balanced and unbalanced forces. A truck at rest doesnot require any attention when parked along a speeds as low as 5m/s may kill a person standing in its path why? What is relation between force and acceleration?

Answer 1

WHEN  THE NET FORCE ACTING ON AN OBJECT IS ZERO ,IT IS CALLED AND BALANCED FORCE .WHEN THE NET FORCE ACTING ON AN OBJECT IS NOT ZERO IT IS CALLED UNBALANCED FORCE.A MOMENTUM OF A TRUCK AT REST IS ZERO THEREFORE NO ATTENTION IS NEEDED.WHEN IT IS IN MOTION THE MOMENTUM IS HUGE EVEN THOUGH IT TRAVELS WITH 5 M/S  BECAUSE THE MOMENTUM IS HUGE AS IT IS IN MOTION AND HAS VERY HUGE MASS.
HOPE IT HELPED..

Answer 2

balanced force is that force where resultant of all the forces are 0 , means all the forces r acting in all directions and therefore no net movement .balanced force can not make a body move but can change the shape on an object.
unbalanced force is the force where the resultant of all the forces is not 0 , means that their is a net movement . unbalanced force can make a body to move and can influence a body to stop.
the momentum of a moving truck is very high though it has a very low acceleration because of  the reason that its mass is very huge.
F=ma ∴ force is directly proportional to the acceleration .
             hope that this will help u and if it help u please mark it as the brainiest one.