A particle of mass 1
kg has potential energy, P. E.

=

3x+4y
. At

t

=0
, the particle is at rest at

(6,4)
. Work done by external force to displace the particle from rest to the point of crossing the x axis is :
-25 J
20 J
15 J
52 J

the answer is 46 mls because when you add the speed per second it increses the speed

the force required to move the cart is divided by three or 33.33 n.

i think it's 35 meters

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.