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3 years ago

Under what conditions is energy conserved

Physics

1 answer:

Alinara [238K]3 years ago

8 0

Answer:

If only internal forces are doing work (no work done by external forces), then there is no change in the total amount of mechanical energy. The total mechanical energy is said to be conserved. ... In these situations, the sum of the kinetic and potential energy is everywhere the same.

Explanation:

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A skateboarder shoots off a ramp with a velocity of 7.3 m/s, directed at an angle of 60° above the horizontal. The end of the ra

erica [24]

Answer:

y maximum 3.54 m, value X 2.35 m

Explanation:

We have a projectile launch problem, let's calculate the maximum height of the projectile, where the vertical speed must be zero

Vyf² = Vyo² - 2g (Y-Yo)

Where Yo is the initial height of the ramp 1.5 m

0 = Vyo² -2g (Y-Yo)

Y-Yo = Voy² / 2g

Y = Yo + Voy² / 2g

Let's calculate the velocity components using trigonometry

Voy = vo without T

Vox = Vo cost

Voy = 7.3 sin 60

Vox = 7.3 cos 60

Voy = 6.32 m / s

Vox = 3.65 m / s

Let's calculate the maximum height

Y = 1.5 +6.32²/2 9.8

Y = 3.54 m

This is the maximum height from the ground

b) They ask us for the position of this point horizontally, we can calculate it looking for the time it took for the skateboarder to reach the highest point

Vfy = Voy - gt

0 = Voy - gt

t = Voy / g

t = 6.32 / 9.8

t = 0.645 s

Since there is no acceleration on the x-axis, we have a uniform movement, we can calculate the distance for this time

X = Vox t

X = 3.65 0.645

X= 2.35 m

8 0

3 years ago

A rear window defroster consists of a long, flat wire bonded to the inside surface of the window. When current passes through th

GenaCL600 [577]

Answer:

$\rho=1.8\times 10^{-8}\Omega.m$

Explanation:

Given:

width of the wire, $w=1.8\ mm=1.8\times 10^{-3}\ m$

thickness of the flat wire, $d=0.12\ mm=1.2\times 10^{-4}$

length of the wire, $l=12\ m$

voltage across the wire, $V=12\ V$

current through the wire, $I=12\ A$

Now the net resistance of the wire:

using ohm's law

$R=\frac{V}{I}$

$R=\frac{12}{12}$

$R=1\ \Omega$

We have the relation between the resistivity and the resistance as:

$R=\rho.\frac{l}{a}$

where:

a = cross sectional area of the wire

$\rho =$ resistivity of the wire material

$1=\rho\times \frac{12}{1.8\times 10^{-3}\times 1.2\times 10^{-4}}$

$\rho=1.8\times 10^{-8}\Omega.m$

4 0

3 years ago

Question 11 of 11 | Page 11 of 11

KiRa [710]

Answer:

Decreases the time period of revolution

Explanation:

The time period of Cygnus X-1 orbiting a massive star is 5.6 days.

The orbital velocity of a planet is given by the formula,

v = √[GM/(R + h)]

In the case of rotational motion, v = (R +h)ω

ω = √[GM/(R + h)] /(R +h)

Where 'ω' is the angular velocity of the planet

The time period of rotational motion is,

T = 2π/ω

By substitution,

Hence, from the above equation, if the mass of the star is greater, the gravitational force between them is greater. This would reduce the time period of revolution of the planet.

3 0

3 years ago

In an inelastic collision, which of the following statements is always true?

xz_007 [3.2K]

Well C is definitely one of the correct answers.

8 0

3 years ago

A 225 kg block is pulled by two horizontal forces. The first force is 178 N at a 41.7-degree angle and the second is 259 N at a

yawa3891 [41]

Answer:

52.9 N, 364.7 N

Explanation: