Question

Betty weighs 432 N and she is sitting on a playground swing seat that hangs 0.41 m above the ground. Tom pulls the swing back and releases it when the seat is 0.94 m above the ground. The acceleration of gravity is 9.8 m/s 2 . How fast is Betty moving when the swing passes through its lowest position? Answer in units of m/s.

Answer 1

v=3.22 m/s

Step-by-step explanation:

This work is stored as gravitational potential energy. When Betty moves through the lowest position, that gravitational potential energy is converted to kinetic energy

`m*g*h=(1)/(2)*m*v^2`

Resolve to v' so:

`m*v^2=2*m*g*h`

`v^2=2*g*h`

Now height is difference of both alture so

`h=0.94m-0.41m`

`h=0.53m`

replacing

`v^2=\sqrt{2*9.8(m)/(s^2)*0.53m}=\sqrt{10.388(m^2)/(s^2)}`

`v=3.22 (m)/(s)`