Question

4. A girl is sitting on a tire swing that is attached with a rope that is 2.1 m in length. Her dad pushes her with a speed of 3.0 m/s. If the centripetal force is 88 N, what is the mass of the girl? ​

Answer 1

The centripetal acceleration is given by
a
=
v
2
r
and Newton's Second Law says
F
=
m
a
, so
F
=
m
v
2
r
. Rearranging,
m
=
F
r
v
2
=
88
⋅
2.1
2.5
2
≈
29.6

k
g
.