Children are sled riding on a hill One little girl pulls her sled back up the hill and does 379.5 joules of work while pulling it back up the 173 meter hill What amount of force did she exert on the sled?

2.2N

Explanation:

Given parameters:

Work done  = 379.5J

Height  = 173m

Unknown:

Amount of force exerted on the sled  = ?

Solution:

The amount of force she exerted on the sled is the same as her weight.

Work done is the force applied to move a body through a distance.

      Work done  = mgh

m is the mass

g is the acceleration due to gravity

h is the height

     mg  = weight;

        Work done  = weight x h

           379.5 = weight  x  173

           weight  =   = 2.2N

according to jean piaget, in what stage of cognitive development are children able to understand conservation task?

b. preoperational

just took it