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A frightened child is restrained by her mother as the child slides down a frictionless playground slide. If the force on the child from the mother is 116 N up the slide, the child's kinetic energy increases by 30 J as she moves down the slide a distance of 1.9 m.
(A) How much work is done on the child by the gravitational force during the 1.9 m descent?
(B) If the child is not restrained by her mother, how much will the child's kinetic energy increase as she comes down the slide that same distance of 1.9 m?

Respuesta :

Answer:

Step-by-step explanation:

Given

Restrained Force [tex]F=116 N[/tex]

Increase in Kinetic Energy [tex]\Delta K.E.=30 J[/tex]

Distance moved d=1.9 m

Work done by all the forces is equal to change in Kinetic Energy of Object i.e. by gravity force, Normal force and Applied Force

[tex]\Delta K.E.=W_g+W_f+W_N[/tex]

[tex]30=W_g-F\cdot d[/tex]

[tex]30=W_g-116\cdot 1.9[/tex]

[tex]W_g=250.4 J[/tex]

(b)In absence of applied force thus

work done by gravity will be equal to  change in kinetic Energy

change in Kinetic Energy[tex]=210 J[/tex]

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