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
OlgaM077 [116]
2 years ago
5

A runner of mass 80 kg is moving at 8.0 m/s. Calculate her kinetic energy. ​

Physics
1 answer:
lana [24]2 years ago
7 0

Answer:

2560J

Explanation:

By definition the kinetic energy can be calculated in the following way:

K = (mv²)/2 = 80kg·(8.0m/s)²/2 = 2560 J

You might be interested in
A bicycle of mass m requires 50 J of work to move from rest to a final speed v. If the same amount of work is performed during t
insens350 [35]

Answer:

The final speed of the second bicycle is (v·√2)/2

Explanation:

The mass of the given bicycle = m

The amount of work required to move the bicycle from rest to speed v = 50 J

The final speed of the first bicycle = v

The mass of the second bicycle = 2m

Therefore, from conservation of energy, we have;

Work required by the first bicycle = Kinetic energy gained by the bicycle

The kinetic energy = 1/2·m·v²

∴ Energy required by the first bicycle = 50 J = 1/2·m·v²

Given that the same amount of work is performed on the second bicycle, we have;

Work performed on the second bicycle = 50 J = kinetic energy of second bicycle = 1/2·(2·m)·v₂²

Also, given that 50 J = 1/2·m·v², we have;

Work performed on the second bicycle = 50 J = 1/2·m·v²= 1/2·(2·m)·v₂²

1/2·m·v²= 1/2·(2·m)·v₂²

m·v² = 2·m·v₂²

v² = 2·v₂²

v₂ = √(v²/2) = v/√2 = (v·√2)/2

v₂ = (v·√2)/2

The final speed of the second bicycle = v₂ = (v·√2)/2.

3 0
3 years ago
A rock group is playing in a bar. Sound emerging from the door spreads uniformly in all directions. The intensity level of the m
LekaFEV [45]

Answer:

1779299.7m

Explanation:

From formulas in acoustic sound, we know that sound intensity is inversely proportional to the square of the distance away.

Thus;

I2/I1 = r2²/r 1²

So,

∆L = 10 log (I2/I1)

Where ∆L is the intensity of music and r1 and r2 are distances away.

∆L=10log 10(r1²/r2²)

∆L=10log 10(r1/r2)²

∆L= - 20log 10(r1/r2)

r2 = r1•10^(-∆L/20)

​From the question,

∆L = 116 Db

r1 = 2.82m

Thus,

r2 = 2.82 x 10^(116/20)

r2 = 2.82 x 630957.34 = 1779299.7m

5 0
3 years ago
Read 2 more answers
Calculate the heat energy needed to change the temperature of 2 kg of copper from 10°C to 110°C.
Stells [14]

Answer:

77000 J

Explanation:

Formula for the heat energy is;

Q = m•c•Δt

We are given;

mass; m = 2 kg

Change in temperature; Δt = 110 - 10 = 100 °C

From online values, specific heat capacity of copper is; c = 385 J/kg.°C

Thus;

Q = 2 × 100 × 385

Q = 77000 J

8 0
3 years ago
Read 2 more answers
What are the rocky planets? theres more in the attachment<br>HELP ME PLS
miss Akunina [59]

Answer:

Explanation:

The rocky planets include Mercury, Venus, Earth, and Mars. they are made up of rocks and metals and have solid surfaces.They are the closest four planets to the Sun. The gas giants are  Neptune, Uranus, Saturn, and Jupiter. they are further from the sun and are in the outer part of the solar system. I hope this helps!

6 0
3 years ago
Please Please I only need help in Questions 4 and 5!
sdas [7]
I'm not sure but for the first one, if there were more electrons than protons that would mean the object would have a positive charge so you could put another object that is positively charged near it, to see if it would attract and if it would it would mean it's negatively charged and if it wouldn't it would mean it's positively charged. (not sure)

for the second one, after you've rubbed the balloon oh hair, the electrons from your hair have transferred onto the balloon, meaning that the balloon is now negatively charged. because the wall is neutral, it means that it has the SAME number of both protons and electrons ( positive and negative charges cancel out to create a neutral charge). because the protons are positively charged, and the balloon is negatively charged, the two objects will attract because opposite charges attract. this happens because of static electricity.

hope this helps :)
4 0
3 years ago
Other questions:
  • Dane is standing on the moon holding an 8 kilogram brick 2 metres above the ground. How much energy is in the brick's gravitatio
    14·2 answers
  • Backpackers often use canisters of white gas to fuel a cooking stove's burner. If one canister contains 1.45 L of white gas, and
    8·1 answer
  • Two airplanes leave an airport at the same time. The velocity of the first airplane is 740 m/h at a heading of 25.3◦. The veloci
    7·1 answer
  • As a fish jumps vertically out of the water, assume that only two significant forces act on it: an upward force F exerted by the
    11·1 answer
  • A 0.50 kilogram ball is held at a height of 20 meters. What is the kinetic energy of the ball when it reaches halfway after bein
    6·1 answer
  • An equipotential surface that surrounds a point charge q has a potential of 536 V and an area of 1.20 m2. Determine q.
    7·1 answer
  • Convert 50cm to metre​
    12·1 answer
  • Warda is driving her car down the street. She has a teddy bear sitting on the back seat. A dog runs in front of Warda's car, so
    7·1 answer
  • How are radar and an approaching siren alike? How are they different?
    14·1 answer
  • Suppose that you changed the area of the bottom surface of the friction cart without changing its mass, by replacing the Teflon
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!