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4 years ago

I need help with air resistance...

1 answer:

3 0

Mar 4, 2004 #1 FabioTTT the formula: R = (.5)DpAv^2 is used to determine how much air resistance (resistive force) is being placed on the object. R is the Resistive force. D is some dimensionless empirical quantity called the drag coefficient p is the density of air A is the cross-sectional area of the object (surface area) v is velocity My question is, is the density of air some constant that should be already given to me? also, how would i go about finding the drag coefficient? I'm asking this because in physics we're doing a lab in wich we drop a cofee filter... and we record its time to reach a certain height (which im guessing is to be able to calulate for the terminal velocity). So in other words, I have all of these variables except for R, D, and p. Can anyone help me out? Phys.org - latest science and technology news stories on Phys.org

Reference https://www.physicsforums.com/threads/need-help-with-air-resistance.15678/

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The magnetic field is decreasing. What is the induced electric field?

melisa1 [442]

Answer: The induced electric field will be constant i.e zero

Explanation:

Magnetic field is a region of space where magnetic force can be felt while electric field is a region of space where electric force can be felt. This two field are related because they tend to talk about force of attraction and repulsion. Example is running a current through a thin wire near a magnet, the direction of one of the field will determine the direction of the other.

According to the question, if the magnetic field is decreasing, the electric field will adjust by traveling in opposite direction to the magnetic field just to make the field constant.

5 0

3 years ago

Identical cannonballs are fired with the same force, one each from four cannons having respective bore lengths of 1.0 meter, 2.0

ANEK [815]

I think its options 2 idk man

6 0

4 years ago

Read 2 more answers

a parent swings a 18.5 kg child in a circle of radius 1.05m, making 5 revolutions in 13.4s. what centripetal acceleration does t

Zolol [24]

Answer: $0.146 m/s^{2}$

Explanation:

The <u>centripetal acceleration</u> $a_{c}$ of an object moving in a uniform circular path is given by the following equation:

$a_{c}=\frac{V^{2}}{r}$ (1)

Where:

$V$ is the tangential velocity

$r=1.05 m$ is the radius of the circle

On the other hand, the tangential velocity is expressed as:

$V=\omega r$ (2)

Where $\omega$ is the angular velocity, which can be found knowing the child makes 5 revolutions in 13.4s:

$\omega=\frac{5 rev}{13.4 s}=0.37 rev/s$ (3)

Substituting (3) in (2):

$V=(0.37 rev/s)(1.05 m)$ (4)

$V=0.39 m/s$ (5)

Substituting (5) in (1):

$a_{c}=\frac{(0.39 m/s)^{2}}{1.05 m}$ (6)

Finally:

$a_{c}=0.146 m/s^{2}$

6 0

3 years ago

Read 2 more answers

A ball is dropped from a height of 10 meters how long was the ball in the air and what is the speed when it hits the ground

Burka [1]

4 Because it will go fast

6 0

3 years ago

A long straight wire carries current to the right of the page. A rectangular loop is positioned directly under the wire in the p

slavikrds [6]

Answer:

Correct option A.

The net force exerted by this loop on the straight wire with the current is directed TOWARDS THE LOOP

Explanation:

The magnetic field exerts a force on a current-carrying wire in a direction given by the right-hand rule 1 (the same direction as that on the individual moving charges). This force can easily be large enough to move the wire since typical currents consist of very large numbers of moving charges.

Given that,

The wire's current is directed towards the right of the page.

The rectangular loops carry current in a clockwise direction.

Since the 'dot' field is increasing hence the induced magnetic field is 'cross', i.e. into the page and by the right-hand rule, the induced current is clockwise.

Then the magnetic field is into the page.

Since was known that

F= iL×B

Note the current is through the wire. Then, the length is in direction of the current.

Note: this equation gives the magnetic force that acts on a length L of a straight wire carrying a current (i) and immersed in a uniform magnetic field (B), that is perpendicular to the wire.

So, the magnetic field is always perpendicular to the current.

So using right hand rule,

F = i(L×B)

The length is to the right i.e. +x direction and the Magnetic field is perpendicular to the plane, i.e. in the +z direction

F = i (L•i × B•k)

F = iLB (i×k)

F = iLB•(-j)

F = -iLB•j

Then, the force is in the negative y-direction i.e. towards the loop.

8 0

4 years ago