1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Naily [24]
3 years ago
13

Give reason 1.electromagnets are temporary magnets ?

Physics
1 answer:
never [62]3 years ago
6 0

they need electricity in order to attract metal. if there's no electric current it would not be able to attract any type of metal.

You might be interested in
Please give an answer that is coherent
Semmy [17]

Answer:

480

Explanation:

resistance equals to potential difference divide by electric current

120÷0.25

=480

6 0
2 years ago
Two vectors are presented as a=3.0i +5.0j and b=2.0i+4.0j find (a) a x b, ab (c) (a+b)b and (d) the component of a along the dir
Svet_ta [14]
Let's ask this question step by step:
 Part A) 
 a x b = (3.0i + 5.0j) x (2.0i + 4.0j) = (12-10) k = 2k
 ab = (3.0i + 5.0j). (2.0i + 4.0j) = 6 + 20 = 26
 Part (c)
 (a + b) b = [(3.0i + 5.0j) + (2.0i + 4.0j)]. (2.0i + 4.0j)
 (a + b) b = (5.0i + 9.0j). (2.0i + 4.0j)
 (a + b) b = 10 + 36
 (a + b) b = 46
 Part (d)
 comp (ba) = (a.b) / lbl
 a.b = (3.0i + 5.0j). (2.0i + 4.0j) = 6 + 20 = 26
 lbl = root ((2.0) ^ 2 + (4.0) ^ 2) = root (20)
 comp (ba) = 26 / root (20)
 answer
 2k
 26
 46
 26 / root (20)
3 0
3 years ago
As air is heated, the particles speed up and spread out (becoming less dense). Hot air balloon pilots can change the balloon’s a
Jobisdone [24]

Answer:

Turn the heater on  

Explanation:

There are two main forces involved in a balloon flight

The downward force is the total weight of the balloon: the air it contains, the gas bag, the basket, the passengers, etc.

The upward force is the weight of the of the air the balloon displaces.

During level flight ,

buoyant force = weight of displaced air - total weight of balloon

If you increase the temperature of the air in the bag, the air molecules spread out and leave through the bottom of the bag.  

The balloon still has the same volume, so the weight of displaced outside air stays the same.

However, the balloon has lost some hot inside air, so its total weight decreases.  

The upward force is greater than the downward force, so the balloon rises.

3 0
3 years ago
When the play button is pressed, a CD accelerates uniformly from rest to 450 rev/min in 3.0 revolutions. If the CD has a radius
Marina CMI [18]

To solve this problem it is necessary to apply the kinematic equations of angular motion.

Torque from the rotational movement is defined as

\tau = I\alpha

where

I = Moment of inertia \rightarrow \frac{1}{2}mr^2 For a disk

\alpha = Angular acceleration

The angular acceleration at the same time can be defined as function of angular velocity and angular displacement (Without considering time) through the expression:

2 \alpha \theta = \omega_f^2-\omega_i^2

Where

\omega_{f,i} = Final and Initial Angular velocity

\alpha = Angular acceleration

\theta = Angular displacement

Our values are given as

\omega_i = 0 rad/s

\omega_f = 450rev/min (\frac{1min}{60s})(\frac{2\pi rad}{1rev})

\omega_f = 47.12rad/s

\theta = 3 rev (\frac{2\pi rad}{1rev}) \rightarrow 6\pi rad

r = 7cm = 7*10^{-2}m

m = 17g = 17*10^{-3}kg

Using the expression of angular acceleration we can find the to then find the torque, that is,

2\alpha\theta=\omega_f^2-\omega_i^2

\alpha=\frac{\omega_f^2-\omega_i^2}{2\theta}

\alpha = \frac{47.12^2-0^2}{2*6\pi}

\alpha = 58.89rad/s^2

With the expression of the acceleration found it is now necessary to replace it on the torque equation and the respective moment of inertia for the disk, so

\tau = I\alpha

\tau = (\frac{1}{2}mr^2)\alpha

\tau = (\frac{1}{2}(17*10^{-3})(7*10^{-2})^2)(58.89)

\tau = 0.00245N\cdot m \approx 2.45*10^{-3}N\cdot m

Therefore the torque exerted on it is 2.45*10^{-3}N\cdot m

3 0
2 years ago
What impact can a very large volcanic eruption have on earths climate
Vaselesa [24]

Answer:

  1. It could instantly kill all life on Earth
  2. It could block out the sun and kill off all plants
  3. It could block out the sun and freeze everything
  4. It could throw sulfur millions of miles and kill everything that 'inhales' it
8 0
3 years ago
Other questions:
  • The picture below shows the weather station model at a particular location.
    10·1 answer
  • What is the magnetic field
    6·2 answers
  • In which direction does a bag at rest move when a force of 20 newtons is applied from the right?
    6·1 answer
  • Gold is called noble gas why
    6·2 answers
  • How to figure out the question?
    14·1 answer
  • Which statement BEST describes the benefits of muscular fitness training?
    13·1 answer
  • you walk 6 block east, 2 blocks north, 3 blocks west and then 2 blocks north. the total distance you travel is blocks
    14·1 answer
  • T02.5 Quiz: Reaction Rates
    15·1 answer
  • Write an essay about Paralympic and Special Olympic Essay 100 points
    8·1 answer
  • Charlie runs at an average speed of 6.5 km/hr. If he runs for 1.5 hours, how far has he traveled?
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!