1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
marin [14]
3 years ago
10

A 72-kg boy is surfing and catches a wave which gives him an initial speed of 1.6 m/s. He then drops through a height of 1.61 m,

and ends with a speed of 8.5 m/s. How much nonconservative work (in kJ) was done on the boy
Physics
1 answer:
chubhunter [2.5K]3 years ago
8 0

Answer:

2849.98 J

Explanation:

From the question,

Work done by the boy = change Potential energy of the boy + change in kinetic energy of the boy

W = ΔP + ΔK..................... Equation 1

Where W = work done by the boy, ΔP = change in potential energy of the boy, ΔK = Change in kinetic energy of the boy.

But,

ΔP = mgΔh.................... Equation 2

ΔK = 1/2mΔv²................. Equation 3

Where m = mass of the boy, Δh = change in height of the boy, Δv = change in velocity of the boy.

Substitute equation 2 and 3 into equation 1

W = mgΔh+1/2mΔv²................. Equation 4

Given: m = 72 kg, Δh = 1.61 m, Δv = 8.5-1.6 = 6.9 m/s, g = 9.8 m/s²

Substitute into equation 4

W = 72(9.8)(1.61)+1/2(72)(6.9²)

W = 1136.016+1713.96

W = 2849.98 J

You might be interested in
A trampoline spring has a force constant k = 800 N/m and is stretched exactly 17.5cm. What is the energy required to do this?
Artist 52 [7]

Answer:

the energy required for the extension is 12.25 J

Explanation:

Given;

force constant of trampoline spring, k = 800 N/m

extension of trampoline spring, x = 17.5 cm = 0.175 m

The energy required for the extension is calculated as;

E = ¹/₂kx²

E = 0.5 x 800 x 0.175²

E = 12.25 J

Therefore, the energy required for the extension is 12.25 J

6 0
3 years ago
Three equal 1.55-μC point charges are placed at the corners of an equilateral triangle whose sides are 0.500 m long. What is the
kati45 [8]

Answer:

0.12959085 J

Explanation:

k = Coulomb constant = 8.99\times 10^{9}\ Nm^2/C^2

q = Charge = 1.55 μC

d = Distance between charge = 0.5 m

Electric potential energy is given by

U=k\dfrac{q^2}{d}

In this system with three charges which are equidistant from each other

U=k\dfrac{q^2}{d}+k\dfrac{q^2}{d}+k\dfrac{q^2}{d}

\\\Rightarrow U=k\dfrac{3q^2}{d}\\\Rightarrow U=8.99\times 10^9\times \dfrac{3\times (1.55\times 10^{-6})^2}{0.5}\\\Rightarrow U=0.12959085\ J

The potential energy of the system is 0.12959085 J

6 0
3 years ago
If he were able to maintain this constant rate of acceleration, what would have been his speed as he finished the race?
Law Incorporation [45]

a) 4.8 m/s² his average acceleration during the first 2.5 s

b) 15 m distance he cover during the first 2.5 seconds.

c) 31 m/s his speed as he finished the race.

<h3>(a) How to calculate the Average Acceleration ?</h3>

Average acceleration is calculated by using Newtons first law of motion

v = u + at

where

u is initial velocity

v is final velocity

a is constant acceleration

t is time

Given u = 0m/s , v = 12 m/s and t = 2.5 sec

Therefore average acceleration is given by

a=\frac{v}{t}

a=\frac{12}{2.5}

a = 4.8 m/sec²

b) Here we will use newtons second law of motion

s=ut+\frac{1}{2}at^{2}

On substituting value we get

s = 15m

c) Here we will use newtons third law of motion

v² = u² + 2as

Here u = 0 , a = 4.8 m/s² and s = 100 m

Therefore

v² = 960

v = 31 m/s

Disclaimer: the question was given incomplete in the portal. Here is the complete question.

Question: Usain Bolt's 100m sprint Runner set the world record for the100 meter sprint during the 2009World Championships in Berlin with a time of 9.58 s, reaching a top speed of 12 m/s in about 2.5 s.

a. What was his average acceleration during the first 2.5 s?

b. What distance did he cover during the first 2.5 seconds, assuming his acceleration was constant?

c. If he were able to maintain this constant rate of acceleration, what would have been his speed as he finished the race?

Learn more about Newtons law of motion here:

brainly.com/question/12525794

#SPJ4

5 0
2 years ago
The mass of a rocket decreases as it burns through its fuel. If the rocket engine produces constant force (thrust), how does the
Serjik [45]

Answer:

it increases-

Explanation:

When the mass of a rocket decreases as it burns through its fuel and the force ( thrust) is constant then by newtons second law of motion

F= ma  here F is constant this means that   ma= constant

⇒ m= F /a    this implies that mass is inversely proportional to  acceleration.

its means when the mass decreases the acceleration must increase. hence the acceleration increases

6 0
3 years ago
How many hydrogen atoms could bind with oxygen
bonufazy [111]
Two would be the answer I believe
5 0
3 years ago
Other questions:
  • Two of the three tuning forks have known frequencies. When a 610 Hz fork and the unknown fork are struck together, four beats pe
    8·1 answer
  • 8. A person with a mass of 15 kg is walking on a flat surface at a velocity of 5 m/s. What is the walker's momentum?
    5·1 answer
  • Which of the following statements is false? In solids, the particles do not move around or change position; they can only vibrat
    11·2 answers
  • "Which particle builds a static electric charge when it is transferred from one object to another?
    11·1 answer
  • Just these 2 question. I have no idea what it's asking..​
    11·1 answer
  • Which of the following statements about digestion is/are TRUE? (Select all that apply.)
    10·2 answers
  • Is this right? Please help me
    7·2 answers
  • "Johnson is throwing rocks at a bug. The bug in response first flies up 117 Cm, then down 32 cm. After dodging another rocks, th
    12·1 answer
  • Present the ways to observe interference patterns on thin films. Why the thickness of thin films should be in scale of wavelengt
    8·2 answers
  • I need help with this problem on science 8th grade here is the picture of the assignment place help me
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!