La densidad del metal disminuye a medida que se calienta . Piense en el agua . Cuando hace frío , se convierte en hielo , lo cual es muy densa . Cuando hace calor , se evapora en gas , que no es denso.
<span>Espero que esto no es confuso , yo no soy un hablante nativo de español .</span>
Answer:
a) 120 N
b) 5 N
c) 0.2 N
d) Mass remains the same, and weight decreases.
Explanation:
<em>Use the formula W = mg, where mass is in kg, and gravitational field strength in N/kg.</em>
a)
W = mg
= 12 × 10
= <u>120 N</u>
b)
500 g = 0.5 kg
W = mg
= 0.5 × 10
= <u>5 N</u>
c)
20 g = 0.02 kg
W = mg
= 0.02 × 10
= <u>0.2 N</u>
d)
<u>Mass remains the same, and weight decreases.</u>
How much gravitational potential energy does the block have
when it gets to the top of the ramp ?
(weight) x (height) = (15 N) x (0.2 m) = 3 Joules .
If there were no friction, you would only need to do 3 Joules of work
to lift the block from the bottom to the top.
But the question says you actually have to do 4 Joules of work
to get the job done.
Friction stole one of your Joules along the way.
Choice-4 is not the correct one.
Choice-1 is the correct one.
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Notice that the mass of the block is NOT 15 kg , and you
don't have to worry about gravity to answer this question.
The formula for potential energy is (m)·(g)·(h) .
But (m·g) is just the WEIGHT, and the formula
is actually (weight)·(height).
The question GIVES us the weight of the block . . . 15 N .
So the potential energy at the top is just (15N)·(0.2m) = 3 Joules.
Two types of mechanical waves: longitudinal<span> waves and </span>transverse<span> waves; the medium movement differs between the two.
</span>In a longitudinal wave the medium particle movement is parallel to the direction of wave propagation; example is sound wave in air.
I<span>n a transverse wave the medium particle movement is perpendicular to the direction of wave propagation; example is mechanical wave on a string.
</span><span>
</span>
The object is farther away then two principles focal lengths from the concave lens