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4 years ago

Which are examples of convection currents ? Select three options.

2 answers:

6 0

Answer: A hot air balloon rising and falling in the atmosphere, a radiator that emits warm air and draws in cool air, and rice moving in a pot of water that is being heated. :)

Ksivusya [100]4 years ago

5 0

Answer:

c e and d

Explanation:

i did the test

You might be interested in

Check all that apply. The magnetic force on the current-carrying wire is strongest when the current is parallel to the magnetic

dedylja [7]

Answer:

The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the field.

The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the current.

The magnetic force on the current-carrying wire is strongest when the current is perpendicular to the magnetic field lines.

Explanation:

The magnitude of the magnetic force exerted on a current-carrying wire due to a magnetic field is given by

$F=ILB sin \theta$ (1)

where I is the current, L the length of the wire, B the strength of the magnetic field, $\theta$ the angle between the direction of the field and the direction of the current.

Also, B, I and F in the formula are all perpendicular to each other. (2)

According to eq.(1), we see that the statement:

"The magnetic force on the current-carrying wire is strongest when the current is perpendicular to the magnetic field lines."

is correct, because when the current is perpendicular to the magnetic field, $\theta=90^{\circ}, sin \theta = 1$ and the force is maximum.

Moreover, according to (2), we also see that the statements

"The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the field. "

"The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the current. "

because F (the force) is perpendicular to both the magnetic field and the current.

5 0

3 years ago

4. How much would an object accelerate if it has a mass of 25 kg and is pushed with a force of 2 Newtons?

slega [8]

Answer:

0.4

Explanation:

f divided by m = a

3 0

3 years ago

A cement factory emits 900 kilograms of CO2 to produce 1,000 kilograms of cement. A fully grown tree removes six kilograms of CO

Ierofanga [76]

Since the factory will be producing 100,000 kilograms of cement, using the relation 1000 kg of cement = 900 kg of CO2, then the factory will be emitting 90,000 kg of CO2 at the same time. To counteract the emission, a tree can remove 6 kg of CO2 per day. Dividing 90,000 kg by 6 kg to know the number of trees, we need 15000 trees to counter the emission. Since 1 acre of land holds 200 trees, we need 75 acres of land to hold the 15000 trees.

3 0

4 years ago

Why does changing the shape of an object have no effect on the density?

iren [92.7K]

Because the object is still made of the same material
Density is not affected by the weight and shape of an object its affected by how concentrated the atoms are in a given volume

7 0

3 years ago

I need help on (a) I don't know what equation to use?

Alchen [17]

Impulse = (force) x (length of time the force lasts)

I see where you doodled (60)(40) over on the side, and you'll be delighted
to know that you're on the right track !

Here's the mind-blower, which I'll bet you never thought of:
On a force-time graph, impulse (also change in momentum)
is just the area that's added under the graph during some time !

From zero to 60, the impulse is just the area of that right triangle
under the graph. The base of the triangle is 60 seconds. The
height of the triangle is 40N . The area of the triangle is not
the whole (base x height), but only 1/2 (base x height).

1/2 (base x height) = 1/2 (60s x 40N) = 1,200 newton-seconds

That's the impulse during the first 60 seconds. It's also the change in
the car's momentum during the first 60 seconds.

Momentum = (mass) x (speed)

If the car wasn't moving at all when the graph began, then its momentum is 1,200 newton-sec after 60 seconds. Through the convenience of the SI system of units, 1,200 newton-sec is exactly the same thing as 1,200 kg-m/s . The car's mass is 3 kg, so after 60 sec, you can write

Momentum = M x V = (3 kg) x (speed) = 1,200 kg-m/s

and the car's speed falls right out of that.

From 60to 120 sec, the change in momentum is the added area of that
extra right triangle on top ... it's 60sec wide and only 20N high. Calculate
its area, that's the additional impulse in the 2nd minute, which is also the
increase in momentum, and that'll give you the change in speed.

8 0

4 years ago