A park merry-go-round consists of a 255 kg circular wooden platform 4.10 m in diameter.?
Four children running alongside push tangentially along the platform's circumference until, starting from rest, the merry-go-round reaches a steady speed of one complete revolution every 2.8 s.
(a) If each child exerts a force of 26 N, how far does each child run?
(b) What is the angular acceleration of the merry-go-round?
(c) How much work does each child do?
(d) What is the kinetic energy of the merry-go-round?

Respuesta :

Answer: a) 12.9 m b) 0.40 rad/s² c) 335.4 J d) 1349.06 J

Explanation:

a)

Distance traveled= R∅

where ∅= [tex]\frac{(2\pi )^2 }{(2.8)^2}[/tex] / 2*α

To find α we have

Sum of torque= Iα

F x r x number of children = m*r²/2 * α

26 x [tex]\frac{4.1}{2}[/tex] * 4 = (255) * (4.10/2)² /2 *α

Solving we get,

α= [tex]\frac{213.2}{535.82}[/tex]

α= 0.40

So,

∅= [tex]\frac{(2\pi )^2 }{(2.8)^2}[/tex] / 2*α

Becomes

∅= 6.29

Now,

Distance traveled= 4.1/2 * 6.29

Distance traveled= 12.9 m

b)

Angular acceleration= 0.40

c)

Work done= F x distance traveled

Work done= 26 x 12.9

Work done= 335.4 J

d)

Kinetic energy= [tex]\frac{1}{2}* I * (\frac{2\pi }{2.8})^2[/tex]

Putting values we get,

Kinetic energy= 267.91 * 5.03

Kinetic energy= 1349.06 J