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3 years ago

13

Why is an object's density expressed as a combination of two units

1 answer:

miss Akunina [59]3 years ago

6 0

Well, first of all, EVERY physical quantity is measured in a combination
of 2 or more units, except for mass, length, time, and electric charge.
ALL other units are made out of these. So it should not surprise you.

[ Example: Speed = (length) / (time) ]

Density is not the mass of a substance. It's the mass of a substance in
a standard volume of it. So the density is made of the mass in any lump
and the volume of that lump. That way, no matter how much of a substance
you have, you can always compare the lump you have to all other substances.

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The graph represents the reaction 2H2 + 02 32H20 as it reaches

Alex

Answer:

C and D

Explanation:

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3 years ago

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What is the mechanical advantage of a nail puller where you exert a force 45 cm from the pivot and the nail is 1.8 cm on the oth

Mandarinka [93]

Answer:

Explanation:

Mechanical Advantage is the ratio of the distance of the input load (Li)from the pivot to the output load applied to the pivot(Lo)

MA = Li/Le

Given;

Li = 45cm

Lo = 1.8cm

MA = 45/1.8

MA = 25

Hence the mechanical advantage is 25

Also MA is expressed in terms of the force ratio which is the ratio of the Load to the effort applied.

MA = Load/Effort

Given

Load = 1250N

MA = 25

Effort = ?

Substitute

25 = 1250/Effort

Effort = 1250/25

Effort = 50N

Hence the minimum force exerted on the load is 50N

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2 years ago

A particle of mass 4.00 kg is attached to a spring with a force constant of 100 N/m. It is oscillating on a frictionless, horizo

zloy xaker [14]

Solution :

Given :

Mass attached to the spring = 4 kg

Mass dropped = 6 kg

Force constant = 100 N/m

Initial amplitude = 2 m

Therefore,

a). $v_{initial} = A w$

$= 2 \times \sqrt{\frac{100}{4}}$

= 10 m/s

Final velocity, v at equilibrium position, v = 5 m/s

Now, $\frac{1}{2}(4+4)5^2 = \frac{1}{2} kA'$

A' = amplitude = 1.4142 m

b). $T=2 \pi \sqrt{\frac{m}{k}}$

m' = 2m

Hence, $T'=\sqrt2 T$

c). $\frac{\frac{1}{2}(4+4)5^2 + \frac{1}{2}\times 4 \times 10^2}{\frac{1}{2} \times 4 \times 10^2}$

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Therefore, factor $=\frac{1}{2}$

Thus, the energy will change half times as the result of the collision.

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2 years ago

Twenty grams of a solid at 70°C is place in 100 grams of a fluid at 20°C. Thermal equilibrium is reached at 30°C.

zaharov [31]

Answer:

c. is more than that of the fluid.

Explanation:

This problem is based on the conservation of energy and the concept of thermal equilibrium

$heat= m s \Delta T
$

m= mass

s= specific heat

\DeltaT=change in temperature

let s1= specific heat of solid and s2= specific heat of liquid

then

Heat lost by solid= $20(s_1)(70-30)=800s_1
$

Heat gained by fluid= $100(s_2)(30-20)=1000s_2
$

Now heat gained = heat lost

therefore,

1000 S_2=800 S_1

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so the specific heat of solid is more than that of the fluid.

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3 years ago

A 600 kg car is at test and then accelerated to 5m/s , what is its original kinetic energy

ycow [4]

Answer:

0 J

Explanation:

Kinetic energy is defined as:

KE = 1/2 m v²

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The car starts at rest, so it has zero velocity. Therefore, its initial kinetic energy is 0 J.

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3 years ago