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3 years ago

Which equation represents the law of conservation of energy in a closed system?

Physics

2 answers:

sladkih [1.3K]3 years ago

8 0

Answer:

A: KEi + PEi = KEf + PEf

Explanation:

on edge

brainliest will be appreciated

Irina-Kira [14]3 years ago

7 0

Answer:

KE + PE = KE + PE

Explanation:

In a closed system, the mechanical energy of the system is constant.

Mechanical energy is given by the sum of kinetic energy and potential energy; mathematically:

U = KE + PE

where

KE is the kinetic energy

PE is the potential energy

This means that if we consider two situations, one at the beginning and one at the end, the value of U will not change if the system is closed; this means that the sum KE + PE will remain the same, so we can write:

KE + PE = KE + PE

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Three particles lie in the xy plane. Particle 1 has mass m1 = 6.7 kg and lies on the x-axis at x1 = 4.2 m, y1 = 0. Particle 2 ha

krek1111 [17]

Answer:

$F=18.58\times 10^{-11}\ N$

$\theta=30.276^{\circ}$

Explanation:

Given:

mass of first particle, $m_1=6.7\ kg$

mass of second particle, $m_2=5.1\ kg$

mass of third particle, $m_3=3.7\ kg$

coordinate position of first particle in meters, $(x_1,y_1)\equiv(4.2,0)$

coordinate position of second particle in meters, $(x_2,y_2)\equiv(0,2.8)$

coordinate position of third particle in meters, $(x_3,y_3)\equiv(0,0)$

Now, gravitational force on particle 3 due to particle 1:

$F_{31}=G\frac{m_1.m_3}{r_{31}^2}$

$F_{31}=6.67\times 10^{-11} \times \frac{6.7\times 3.7}{4.2^2}$

$F_{31}=9.37\times 10^{-11}\ N$

towards positive Y axis.

gravitational force on particle 3 due to particle 2:

$F_{32}=G\frac{m_2.m_3}{r_{21}^2}$

$F_{32}=6.67\times 10^{-11} \times \frac{5.1\times 3.7}{2.8^2}$

$F_{32}=16.05\times 10^{-11}\ N$

towards positive X axis.

Now the net force

$F=\sqrt{F_{31}\ ^2+F_{32}\ ^2}$

$F=\sqrt{(10^{-11})^2(9.37^2+16.05^2)}$

$F=18.58\times 10^{-11}\ N$

For angle in counterclockwise direction from the +x-axis

$tan\theta=\frac{9.37\times 10^{-11}}{16.05\times 10^{-11}}$

$\theta=30.276^{\circ}$

4 0

3 years ago

A moped has a mass of 120kg . It accelerates at a rate of 2 m/s^2 . What is the size of the resultant force acting on it ?

stiv31 [10]

Answer:

240N

Explanation:

The formula for force is F=mass×acceleration.

Therefore, Force= 120×2= 240N

7 0

4 years ago

Different ____ of light through two separate mediums causes the bending of waves fronts associated with light rays.

Fittoniya [83]

Different speeds of light through two separate media ... and the difference in wavelength caused by the difference ... causes the bending of waves fronts associated with light rays.

AFTER the bend, since the light rays then travel in a different direction, we may also say that the 'velocity' has changed.

8 0

3 years ago

3.25 kcal is the same amount of energy as

PIT_PIT [208]

1 cal = 4,185 J
1 kcal = 1*10^3 cal
or
=1000 cal

8 0

3 years ago

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IrinaK [193]

Answer: