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2 years ago

Gravitational potential energy (Eg) and kinetic energy (Ek)

Physics

2 answers:

STatiana [176]2 years ago

6 0

Answer:

hope it will help you

Explanation:

madreJ [45]2 years ago

4 0

Answer:

$\boxed {\boxed {\sf E_K= \ 5,040 \ J}}$

Explanation:

Kinetic energy is the energy an object possesses due to motion. It is calculated using the following formula:

$E_K= \frac{1}{2} mv^2$

The mass of the athlete is 70.0 kilograms. The velocity is 12 meters per second.

m= 70.0 kg
v= 12 m/s

Substitute the values into the formula.

$E_K= \frac{1}{2} (70.0 \ kg)(12 \ m/s)^2$

Solve the exponent.

(12 m/s)² = (12 m/s)(12 m/s) = 144 m²/s²

$E_K= \frac{1}{2} (70.0 \ kg)(144 \ m^2/s^2)$

Multiply the numbers together.

$E_K= \frac{1}{2} (10, 080 \ kg*m^2/s^2)$

$E_K= 5,040 \ kg*m^2/s^2$

Convert the units. 1 kilogram meter squared per second squared is equal to 1 Joule, so our answer is equal to 5,040 Joules.

$E_K= 5.040 \ J$

The athlete has <u>5,040 Joules</u> of kinetic energy.

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SCALCET8 3.9.018.MI. A spotlight on the ground shines on a wall 12 m away. If a man 2 m tall walks from the spotlight toward the

Firlakuza [10]

Answer:

The length of his shadow is decreasing at a rate of 1.13 m/s

Explanation:

The ray of light hitting the ground forms a right angled triangle of height H, which is the height of the building and width, D which is the distance of the tip of the shadow from the building.

Also, the height of the man, h which is parallel to H forms a right-angled triangle of width, L which is the length of the shadow.

By similar triangles,

H/D = h/L

L = hD/H

Also, when the man is 4 m from the building, the length of his shadow is L = D - 4

So, D - 4 = hD/H

H(D - 4) = hD

H = hD/(D - 4)

Since h = 2 m and D = 12 m,

H = 2 m × 12 m/(12 m - 4 m)

H = 24 m²/8 m

H = 3 m

Since L = hD/H

and h and H are constant, differentiating L with respect to time, we have

dL/dt = d(hD/H)/dt

dL/dt = h(dD/dt)/H

Now dD/dt = velocity(speed) of man = -1.7 m/s ( negative since he is moving towards the building in the negative x - direction)

Since h = 2 m and H = 3 m,

dL/dt = h(dD/dt)/H

dL/dt = 2 m(-1.7 m/s)/3 m

dL/dt = -3.4/3 m/s

dL/dt = -1.13 m/s

So, the length of his shadow is decreasing at a rate of 1.13 m/s

5 0

2 years ago

A steel cable has a cross-sectional area 4.49 × 10^-3 m^2 and is kept under a tension of 2.96 × 10^4 N. The density of steel is

Lemur [1.5K]

Answer:

The transverse wave will travel with a speed of 25.5 m/s along the cable.

Explanation:

let T = 2.96×10^4 N be the tension in in the steel cable, ρ = 7860 kg/m^3 is the density of the steel and A = 4.49×10^-3 m^2 be the cross-sectional area of the cable.

then, if V is the volume of the cable:

ρ = m/V

m = ρ×V

but V = A×L , where L is the length of the cable.

m = ρ×(A×L)

m/L = ρ×A

then the speed of the wave in the cable is given by:

v = √(T×L/m)

= √(T/A×ρ)

= √[2.96×10^4/(4.49×10^-3×7860)]

= 25.5 m/s

Therefore, the transverse wave will travel with a speed of 25.5 m/s along the cable.

7 0

3 years ago

A mover pushes a 46.0kg crate 10.3m across a rough floor without acceleration. How much work did the mover do (horizontally) pus

Alchen [17]

Answer:

<h3>2,321.62Joules</h3>

Explanation:

The formula for calculating workdone is expressed as;

Workdone = Force * Distance

Get the force

F = nR

n is the coefficient of friction = 0.5

R is the reaction = mg

R = 46 ( 9.8)

R = 450.8N

F = 0.5 * 450.8

F = 225.4N

Distance = 10.3m

Get the workdone

Workdone = 225.4 * 10.3

Workdone = 2,321.62Joules

<em>Hence the amount of work done is 2,321.62Joules</em>

3 0

3 years ago

The convection zone is the outer most layer of the suns blank hot gases rise and then blank hear the loops form by singing cool

lora16 [44]

Answer:

Explanation:

The sun is made up of 6 parts. Namely:

The core
The radiation zone
The convection zone
The photosphere
The chromosphere and
The corona

The convection area is just above the radiation zone. As materials from the suns core are heated, they rise above the radiation zone towards the EDGE of the convection area then sinks back again into the radiative zone for more heat.

The radiative zone is 12.6 million Fahrenheit hot and is just above the core.

The core of the son is not solid but plasma whose motion is like gas. Its temperature stands at 48 million Fahrenheit

Cheers

5 0

3 years ago

A sound wave is called a longitudinal wave? why?Give reason

Mars2501 [29]

Answer:

A sound wave is called a longitudinal wave because compressions and rarefactions in the air produce it. The air particles vibrate parallel to the direction of propagation.

3 0

3 years ago