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3 years ago

When a piece of aluminium foil is taken out of the oven and cools from 1000C to 500C. What is the change in temperature?

Physics

1 answer:

zmey [24]3 years ago

3 0

Answer:

Conduction

Explanation:

When one object touches another heat moves through it (think of a saucepan on a hot stove). Aluminium foil is a great conductor of heat, which means it is a poor insulator when it is in direct contact with something hot.

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HELP ME ASAP!!!!100 points!!!!! How do you get your fingers in the Labia?

Nina [5.8K]

You literally just put your fingers in your genitals? is this for a sex ed course...?

4 0

3 years ago

Read 2 more answers

A tennis ball is dropped from a roof. If it takes 38.9 seconds to reach the ground, how fast is the ball moving just before it h

Ilya [14]

Answer:

The velocity of the ball before it hits the ground is 381.2 m/s

Explanation:

Given;

time taken to reach the ground, t = 38.9 s

The height of fall is given by;

h = ¹/₂gt²

h = ¹/₂(9.8)(38.9)²

h = 7414.73 m

The velocity of the ball before it hits the ground is given as;

v² = u² + 2gh

where;

u is the initial velocity of the on the root = 0

v is the final velocity of the ball before it hits the ground

v² = 2gh

v = √2gh

v = √(2 x 9.8 x 7414.73 )

v = 381.2 m/s

Therefore, the velocity of the ball before it hits the ground is 381.2 m/s

5 0

2 years ago

An object is dropped onto the moon (gm = 5 ft/s2). How long does it take to fall from an elevation of 250 ft.?

anyanavicka [17]

Answer:

10 seconds

Explanation:

x = x₀ + v₀ t + ½ at²

250 = 0 + (0) t + ½ (5) t²

250 = 2.5 t²

t² = 100

t = 10

It takes 10 seconds to land from a height of 250 ft.

8 0

3 years ago

Read 2 more answers

A cube-shaped piece of copper has sides of 4cm each and it's density is

iris [78.8K]

Answer:

$64 cm^3$

Explanation:

Density

The density of a substance is the mass per unit volume. The density varies with temperature and pressure.

The formula to calculate the density of a substance of mass (m) and volume (V) is:

$\displaystyle \rho=\frac{m}{V}$

We have a cube-shaped piece of copper of 4 cm of side length. The volume of the piece is:

$V=(4\ cm)^3=64\ cm^3$

Surprisingly, no other magnitude is required, thus the answer is:

$\mathbf{64 cm^3}$

5 0

2 years ago

An investigator collects a sample of a radioactive isotope with an activity of 490,000 Bq.48 hours later, the activity is 110,00

Daniel [21]

Answer:

The correct answer is "22.27 hours".

Explanation:

Given that:

Radioactive isotope activity,

= 490,000 Bq

Activity,

= 110,000 Bq

Time,

= 48 hours

As we know,

⇒ $A = A_0 e^{- \lambda t}$

or,

⇒ $\frac{A}{A_0}=e^{-\lambda t}$

By taking "ln", we get

⇒ $ln \frac{A}{A_0}=- \lambda t$

By substituting the values, we get

⇒ $-ln \frac{110000}{490000} = -48 \lambda$

⇒ $-1.4939=-48 \lambda$

$\lambda = 0.031122$

As,

⇒ $\lambda = \frac{ln_2}{\frac{T}{2} }$

then,

⇒ $\frac{ln_2}{T_ \frac{1}{2} } =0.031122$

⇒ $T_\frac{1}{2}=\frac{ln_2}{0.031122}$

$=22.27 \ hours$

3 0

3 years ago