A 28.0 kg child plays on a swing having support ropes that are 2.30 m long. A friend pulls her back until the ropes are 45.0 ∘ from the vertical and releases her from rest.
A: What is the potential energy for the child just as she is released, compared with the potential energy at the bottom of the swing?
B: How fast will she be moving at the bottom of the swing?
C: How much work does the tension in the ropes do as the child swings from the initial position to the bottom?

Question

05-08-2020
Physics

contestada

A 28.0 kg child plays on a swing having support ropes that are 2.30 m long. A friend pulls her back until the ropes are 45.0 ∘ from the vertical and releases her from rest.
A: What is the potential energy for the child just as she is released, compared with the potential energy at the bottom of the swing?
B: How fast will she be moving at the bottom of the swing?
C: How much work does the tension in the ropes do as the child swings from the initial position to the bottom?

Respuesta :

Otras preguntas

What are the 4 elements of a virus structure

Am Bk FMA 6. How many unfilled orbitals does Sulfur (S) have? How many half-filled orbitals does it have? 7. An element's electron configuration is 1s²2s²3s²3p

Which of the following could be a real-world description of the quantity two times x end quantity divided by 10? The cost of a pizza split by 10 people plus a $

What should professionals in the medical field or psychology field keep in mind when creating a positive patient experience? Select one: socioeconomic status of

What is the most common economic activity in the Sahel?

he value of x varies directly with y, and when x=1/3, y=5

1) What is geography? How has the climate, influenced where people have were distributed in the Ancient American Civilization time?

Explain Roosevelts foreign policy

The trabeculae of spongy bone are oriented somewhat randomly but towards lines of stress, making them useful in preventing stress from many directions. True or

What was Germany's intention for the Zimmermann Telegram?

ayfat23 ayfat23 · Answer 1 · 2020-08-05T06:32:07+02:00

Answer

A)184.9J

B)=3.63m/s

C) Zero

Explanation:

A)potential energy of the child at the initial position, measured relative the her potential energy at the bottom of the motion, is

U=Mgh

Where m=28kg

g= 9.8m/s

h= difference in height between the initial position and the bottom position

We are told that the rope is L = 2.30 m long and inclined at 45.0° from the vertical

h=L-Lcos(x)= L(1-cosx)=2.30(1-cos45)

=0.674m

Her Potential Energy will now

= 28× 9.8×0.674

=184.9J

B)we can see that at the bottom of the motion, all the initial potential energy of the child has been converted into kinetic energy:

E= 0.5mv^2

where

m = 28.0 kg is the mass of the child

v is the speed of the child at the bottom position

Solving the equation for v, we find

V=√2k/m

V=√(2×184.9/28

=3.63m/s

C)we can find work done by the tension in the rope is given using expresion below

W= Tdcosx

where W= work done

T is the tension

d = displacement of the child

x= angle between the directions of T and d

In this situation, we have that the tension in the rope, T, is always perpendicular to the displacement of the child, d. x= 90∘ and cos90∘=0 hence, the work done is zero.