1. a rope attaches a tire to an overhanging tree limb. a girl swinging on the tire has a
centripetal acceleration of 3.0 m/s2. if the length of the rope is 2.1 m, what is the girl's
tangential speed?

2.51 m/s

Explanation:

Formula for Centripetal Acceleration

a_{c} =\frac{v^{2} }{r}

where v= velocity of the girl swinging through a rope  and

r=radius of the circle she is moving in ie. the length of the rope assuming its attached till the center of the tire of negligible dimension.

Given

m/

r=2.1 m

v=??(in m)

Plugging in the values

3 =\frac{v^{2} }{2.1}

=3 × 2.1

= 6.3

v=

v=2.5099 m/s ≈ 2.51 m/s

option number c is the right answer.

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.