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Natasha2012 [34]
2 years ago
7

Which of the following is an example of a chemical change?

Physics
1 answer:
tankabanditka [31]2 years ago
3 0

b. burning paper

hope it helps

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A machine that operates a ride at the fair requires 2500 J to lift a 294 N child 5.0 m. What is the efficiency of this machine?
NeX [460]

Answer:

η = 58.8%

Explanation:

Work is defined as the force applied by the distance traveled by the body.

W =F*d

where:

W = work [J] (units of joules)

F = force = 294 [N]

d = distance = 5 [m]

W = 294*5\\W = 1470 [J]\\

Efficiency is defined as the energy required to perform an activity in relation to the energy actually added to perform some activity. This can be better understood by means of the following equation.

efficiency = W_{done}/W_{required}\\efficiency = 1470/2500\\efficiency = 0.588 = 58.8%

5 0
3 years ago
Object A has a mass of 100 grams. Object B has a mass of 150 grams. They are both traveling at the same velocity. What can you c
Scilla [17]
-- Momentum is (mass) x (speed). 
Object B has 1.5 times as much momentum as Object A has.

-- Kinetic energy is (1/2) x (mass) x (speed) . 
Object B has 1.5 times as much kinetic energy as Object A has.

-- If they would both stop long enough to get on the scale,
Object B would weigh 1.5 times as much as Object A does.
8 0
3 years ago
Which describe the image formed by an object in
iris [78.8K]

Answer:

In a concave mirror, if an object is located between the center of curvature and the focal point, what is the best way to describe the image formed? Real, inverted, and smaller than the object. Real, inverted, and larger than the object. light rays travel parallel to each other, no other image is formed.

3 0
4 years ago
Read 2 more answers
Can energy be neither created nor destroyed by ordinary means
IgorLugansk [536]

A pure substance that cannot be decomposed by ordinary chemical change. . Energy can be converted from one form to another, but it cannot be created or destroyed in ordinary chemical or physical means.

8 0
3 years ago
En la Tierra un volcán puede expulsar rocas verticalmente hasta una altura máxima H. A) ¿A qué altura (en términos de H) llegarí
Nonamiya [84]

A) 2.64 H

The maximum height that the expelled rock can reach can be found by using the equation:

v^2-u^2 = 2gd

where

v = 0 is the velocity at the maximum height

u is the initial velocity

g is the acceleration of gravity

d is the maximum height

Solving for d,

d=\frac{-u^2}{2g}

We see that the maximum heigth is inversely proportional to g. On the Earth,

d=H and g=g_e = -9.81 m/s^2

So we can write:

\frac{H}{H'}=\frac{g_m}{g_e}

where H' is the maximum height reached on Mars, and g_m = -3.71 m/s^2 is the acceleration of gravity on Mars. Solving for H',

H' = \frac{g_e}{g_m}H = \frac{-9.81}{3.71}H=2.64 H

B) 2.64T

The time after which the rock reaches the maximum height can be found by using

v=u+gt

where

v = 0 is the velocity at the maximum height

u is the initial velocity

Solving for t,

t=\frac{v-u}{g}

The total time of the motion is twice this value, so:

t=2\frac{v-u}{g}

So we see that it is inversely proportional to g.

On the Earth, t = T. So we can write:

\frac{T}{T'}=\frac{g_m}{g_E}

where T' is the total time of the motion on Mars. Solving for T',

T' = \frac{g_e}{g_m}T=\frac{-9.81}{-3.71}T=2.64T

4 0
3 years ago
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