# PHYSICS

posted by .

A 27.0 kg child on a 3.00 m long swing is released from rest when the swing supports make an angle of 31.0° with the vertical. Neglecting friction, find the child's speed at the lowest position.

• PHYSICS -

mass is irrelevant for pendulum, cancels
Figure out how high the child is above the low point when the chains are 31 deg from vertical
h = 3 (1 - cos 31)
U at top = m g h
Ke at bottom = U at to
(1/2) m v^2 = m g h
v = sqrt (2 g h)

• PHYSICS -

thanks!

• PHYSICS -

If the speed of the child at the lowest position is 2.50 m/s, what is the mechanical energy lost due to friction?

• PHYSICS -

mechanical energy lost= PE at top-1/2 m vb^2 where vb is the speed at the bottom

## Similar Questions

1. ### physics

Draw the figure, and calcuate the height above the bottom point the swing starts. (I remember it as 2.3(1-cos25)). the initial energy is mg*height. The final energy is 1/2 m v^2 The difference is frction. A 49 kg child on a 2.3 m long …
2. ### physics

A 25kg child on a 2m long swing is released from rest when the swing supports make an angle of 30 degrees with the vertical. (a) Neglecting friction, find the child's speed at the lowest position. (b) If the speed of the child at the …
3. ### Physics

A 40.0kg child is in a swing that is attached to ropes 2.00m long. Find the gravitational potential energy associated with the child relative to the child's lowest position under the following conditions: a) When the ropes are horizontal …
4. ### physics

A 350 N child is in a swing attached to rope 1.75m long. Find the gravitational PE associated with the child relative to her lowest position when the ropes make a 30 degree angle with the vertical
5. ### physics

A 120 N child is in a swing that is attached to ropes 2.20 m long. Find the gravitational potential energy of the child-Earth system relative to the child's lowest position at the following times. (a) when the ropes are horizontal …
6. ### Physics Energy and Work Done

A 390-N child is in a swing that is attached to a pair of ropes 1.9 m long. Find the gravitational potential energy (in JOULES) of the child–Earth system relative to the child's lowest position at the following times. A) when the …
7. ### Physics

A 350 N child is in a swing that is attached to a 7.50 m long rope. find the gravitational potential energy associated with the child relative to her lowest position when a) the ropes are horizontal, (b) the ropes make a 30 degree …
8. ### physics

a parent pushes a kid on a swing, A) If the child on the swing rises 2m above the lowest point during each cycle, what is her speed at the lowest point of the swing?
9. ### Physics

A 22kg child on a 1.75m long swing is released from rest when the swing supports make an angle of 35 degrees with the vertical. 1.What is the child's maximum potential energy?
10. ### physics

A 25.0-kg child on a 3.00-m-long swing is released from rest when the ropes of the swing make an angle of 31.0° with the vertical. (a) Neglecting friction, find the child's speed at the lowest position. m/s (b) If the actual speed …

More Similar Questions