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
scZoUnD [109]
3 years ago
15

What is Electromagnet? What is Voltage?

Physics
1 answer:
vampirchik [111]3 years ago
8 0

Answer: a core of magnetic material

Explanation:

A core of magnetic material surrounded by a coil of write through which an electric current is passed to magnetize the core

You might be interested in
A boy throws a ball into the air at 10.2 m/s. Assuming that only gravity acts on the ball, how high does it rise, in m?
ozzi
Answer: 5.31 meters

Explanation: Use conservation of energy. Initial energy equals final energy. Initially, there is only kinetic energy (because height = 0 initially). At the end, kinetic energy equals 0 because at max height, there is max potential energy and the ball stops moving for a split second.

mgh = .5mv^2
Masses cancel out
gh = .5v^2
(9.8)(h) = .5(10.2^2)
Solve for h. h = 5.31 meters
5 0
2 years ago
Suppose you exert 150 n on your refrigerator and push it across the kitchen floor at constant velocity. what friction force acts
Pachacha [2.7K]
Due that the velocity is constant that means that friction force is equal to the force exert by you, otherwise the refrigerator will accelerate or decelerate and in both cases velocity will not be constant.  
So then the friction force between refrigerator and floor is 150 Newtons.
8 0
3 years ago
Read 2 more answers
3. The electric field of a sinusoidal electromagnetic wave has an amplitude of 5.0 V/m. How much radiation energy passes through
True [87]

Answer:

e) 179 J

Explanation:

E_{o} = Magnitude of electric field = 5 V/m

A = Area of window = 1.5 m²

c = speed of electromagnetic wave = 3 x 10⁸ m/s

\Delta t = time interval = 1 h = 3600 sec

radiation energy is given as

U = (0.5)\epsilon _{o}E_{o}^{2}cA\Delta t

U = (0.5)(8.85\times 10^{-12})(5)^{2}(3\times 10^{8})(1.5)(3600)

U = 179 J

6 0
2 years ago
Two workers are sliding 300 kg crate across the floor. One worker pushes forward on the crate with a force of 400 N while the ot
almond37 [142]

Answer:

The kinetic coefficient of friction of the crate is 0.235.

Explanation:

As a first step, we need to construct a free body diagram for the crate, which is included below as attachment. Let supposed that forces exerted on the crate by both workers are in the positive direction. According to the Newton's First Law, a body is unable to change its state of motion when it is at rest or moves uniformly (at constant velocity). In consequence, magnitud of friction force must be equal to the sum of the two external forces. The equations of equilibrium of the crate are:

\Sigma F_{x} = P+T-\mu_{k}\cdot N = 0 (Ec. 1)

\Sigma F_{y} = N - W = 0 (Ec. 2)

Where:

P - Pushing force, measured in newtons.

T - Tension, measured in newtons.

\mu_{k} - Coefficient of kinetic friction, dimensionless.

N - Normal force, measured in newtons.

W - Weight of the crate, measured in newtons.

The system of equations is now reduced by algebraic means:

P+T -\mu_{k}\cdot W = 0

And we finally clear the coefficient of kinetic friction and apply the definition of weight:

\mu_{k} =\frac{P+T}{m\cdot g}

If we know that P = 400\,N, T = 290\,N, m = 300\,kg and g = 9.807\,\frac{m}{s^{2}}, then:

\mu_{k} = \frac{400\,N+290\,N}{(300\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)}

\mu_{k} = 0.235

The kinetic coefficient of friction of the crate is 0.235.

5 0
2 years ago
A thermometer initially reading 212F is placed in a room where the temperature is 70F. After 2 minutes the thermometer reads 125
frez [133]

Answer:

91.3°F

Explanation:

Let T be the temperature of the thermometer at any time

T∞ be the temperature of the room = 70°F

T₀ be the initial temperature of the thermometer = 212°F

And m, c, h are all constants from the cooling law relation

From Newton's law of cooling

Rate of Heat loss by the cake = Rate of Heat gain by the environment

- mc (d/dt)(T - T∞) = h (T - T∞)

(d/dt) (T - T∞) = dT/dt (Because T∞ is a constant)

dT/dt = (-h/mc) (T - T∞)

Let (h/mc) be k

dT/(T - T∞) = -kdt

Integrating the left hand side from T₀ to T and the right hand side from 0 to t

In [(T - T∞)/(T₀ - T∞)] = -kt

(T - T∞)/(T₀ - T∞) = e⁻ᵏᵗ

(T - T∞) = (T₀ - T∞)e⁻ᵏᵗ

Inserting the known variables

(T - 70) = (212 - 70)e⁻ᵏᵗ

(T - 70) = 142 e⁻ᵏᵗ

At t = 2 minute, T = 125°F

125 - 70 = 142 e⁻ᵏᵗ

55/142 = e⁻ᵏᵗ

- kt = In (55/142) = In (0.3873)

- k(2) = - 0.9485

k = 0.4742 /min

At time t = 4 mins

kt = 0.4742 × 4 = 1.897

(T - 70) = 142 e⁻ᵏᵗ

e^(-1.897) = 0.15

T - 70 = 142 × 0.15 = 21.3

T = 91.3°F

7 0
3 years ago
Other questions:
  • An elevator is moving upward at a constant speed of 2.50 m/s. A bolt in the elevator ceiling 3.00 m above the elevator floor wor
    7·1 answer
  • Legal concept establishing that evidence speaks for itself
    15·1 answer
  • Find the kinetic energy of a 0.1-kilogram toy truck moving at the speed of 1.1 meters per second.
    14·1 answer
  • A student weighing 700 N climbs at constant speed to the top of an 8 m vertical rope in 10 s. The average power expended by the
    13·1 answer
  • n object is undergoing uniform circular motion. Which of the following is/are true? I. The object is moving at constant velocity
    6·1 answer
  • An object with a mass of 300 kg is
    11·2 answers
  • Calculate the moment of inertia and the rotational kinetic energy for the following objects spinning about a central axis (in un
    7·1 answer
  • What is a major risk for heart disease that you cannot control A obesity b heredity c smoking d physical inactivity
    13·1 answer
  • Two people are talking at a distance of 3.0 m from where you are, and
    8·1 answer
  • If a car drives 10 miles NE and then due East for 10 minutes traveling 8
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!