Author Question: A playground merry-go-round with a radius of 2.0 m and a rotational inertia of 100 kg m2 is rotating ... (Read 130 times)

pragya sharda · **on:** Jul 29, 2018

A playground merry-go-round with a radius of 2.0 m and a rotational inertia of 100 kg m2 is rotating at 3.0 rad/s.

A child with a mass of 22 kg jumps onto the edge of the merry-go-round, traveling radially inward. What is the new angular speed of the merry-go-round?
A)

1.6 rad/s

B)

1.2 rad/s

C)

2.4 rad/s

D)

2.0 rad/s

E)

3.4 rad/s

Question 2

Calculate the radius that a loop should have so that the magnetic energy density at its center is equal to 6 mJ/ m3 when a current I = 20A passes through the loop?

A)

26 cm
B)

10 cm
C)

7 cm
D)

18 cm
E)

15 cm