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andreyandreev [35.5K]
3 years ago
10

What advantages does an electromagnet have over a permanent magnet?

Physics
1 answer:
KonstantinChe [14]3 years ago
4 0
Electromagnets can be turned off, this makes it easier to release things from the magnetic field. 

Hope this helps :)
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VP 3.12.1 Part APart complete A cyclist going around a circular track at 10.0 m/s has a centripetal acceleration of 5.00 m/s2. W
viktelen [127]

Answer:

A) r = 20.0 m

B) T = 41.6 s

C) = 6.1 m/s²

Explanation:

A)

  • The centripetal acceleration is the one that explains that even though the cyclist is moving at a constant speed, his velocity is changing the direction all the time, keeping him around a circle.
  • This acceleration can be expressed as follows:

        a_{c} =\frac{v^{2}}{r} = \frac{(10.0m/s)^{2}}{r} = 5.00 m/s2  (1)

  • Solving for r:

       r = \frac{v^{2}}{a_{c} } = \frac{(10.0m/s)^{2}}{5.00m/s2} = 20.0 m  (2)

B)

  • We can apply the definition of linear velocity, remembering that the period is the time needed to complete an entire circle (T).
  • The arc around a circumference (the distance traveled) , is just 2*π*r, so applying the definition of linear velocity, we can write the following expression:

        v = \frac{\Delta s}{\Delta t} = \frac{2*\pi*r}{T} (3)

  • Solving  for T:

       T = \frac{\Delta s}{v} = \frac{2*\pi*r}{v} = \frac{2*\pi*265m}{40.0m/s} =41.6 s  (4)

C)

  • The centripetal acceleration of the car from B) can be found as follows:

        a_{c} =\frac{v^{2}}{r} = \frac{(40.0m/s)^{2}}{265m} = 6.1 m/s2   (5)

4 0
2 years ago
In a little league baseball game, the 145 g ball enters the strike zone with a speed of 14.0m/s . the batter hits the ball, and
Novosadov [1.4K]

Answer:

5365 N

Explanation:

v = Final velocity = 23 m/s

u = Initial velocity = -14 m/s (opposite direction)

m = Mass of ball = 145 g

t = Time taken = 1 ms

Impulse is given by

J=m(v-u)

Impulse is also given by

J=Ft

Ft=m(v-u)\\\Rightarrow F=\dfrac{m(v-u)}{t}\\\Rightarrow F=\dfrac{0.145\times (23-(-14))}{1\times 10^{-3}}\\\Rightarrow F=5365\ N

The magnitude of the average force exerted by the bat on the ball is 5365 N

8 0
3 years ago
A pendulum consists of a 1.7-kg block hanging on a 1.6-m length string. A 0.01-kg bullet moving with a horizontal velocity of 82
Rzqust [24]

Answer:

0.42 m

Explanation:

mass of pendulum, M = 1.7 kg

Length of pendulum , l = 1.6 m

mass of bullet, m = 0.01 kg

initial velocity of bullet, u = 828 m/s

final velocity of bullet, v = 340 m/s

initial velocity of pendulum, U = 0

Let the final velocity of pendulum is V.

Use conservation of momentum for bullet and the pendulum

m x u + M x U = m x v + M x V

0.01 x 828 + 1.7 x 0 = 0.01 x 340 + 1.7 x V

8.28 + 0 = 3.4 = 1.7 V

V = 2.87 m/s

Now the kinetic energy of the pendulum is converted into potential energy of pendulum and let it raised to a height of h from the initial level.

Use energy conservation

Kinetic energy of the pendulum  = potential energy of the pendulum

0.5 x M x V² = M x g x h

0.5 x 2.87 x 2.87 = 9.8 x h

h = 0.42 m

6 0
3 years ago
What was David Berkowitz best known for? How did arson play a role in his past?
tankabanditka [31]
David Berkowitz, who became known as Son of Sam, went on a murderous rampage in New York City during the 1970s, taunting and insulting police, until they captured him. On August 10, 1977, 11 days after his last murder, David Berkowitz, known as Son of Sam, was arrested and later sentenced to six consecutive 25-years-to-life terms. Arson has evolved, since the 18th century, from a wrongful individual act into an effective means of collective violence, too. From 1750, the privatisation of common land in England limited peasants' access to resources such as firewood and game. Hope this helped!
5 0
3 years ago
Read 2 more answers
The density of gasoline is 730 kg/m3 at 0°C. Its average coefficient of volume expansion is 9.60 10-4(°C)−1. Assume 1.00 gal of
kipiarov [429]

Answer: 0.4911 kg

Explanation:

We have the following data:

\rho_{0\°C}= 730 kg/m^{3} is the density of gasoline at 0\°C

\beta=9.60(10)^{-4} \°C^{-1} is the average coefficient of volume expansion

We need to find the extra kilograms of gasoline.

So, firstly we need to transform the volume of gasoline from gallons to m^{3}:

V=8.50 gal \frac{0.00380 m^{3}}{1 gal}=0.0323 m^{3} (1)

Knowing density is given by: \rho=\frac{m}{V}, we can find the mass m_{1} of 8.50 gallons:

m_{1}=\rho_{0\°C}V

m_{1}=(730 kg/m^{3})(0.0323 m^{3})=23.579 kg (2)

Now, we have to calculate the factor f by which the volume of gasoline is increased with the temperature, which is given by:

f=(1+\beta(T_{f}-T_{o})) (3)

Where T_{o}=0\°C is the initial temperature and T_{f}=21.7\°C is the final temperature.

f=(1+9.60(10)^{-4} \°C^{-1}(21.7\°C-0\°C)) (4)

f=1.020832 (5)

With this, we can calculate the density of gasoline at 21.7\°C:

\rho_{21.7\°C}=730 kg/m^{3} f=(730 kg/m^{3})(1.020832)

\rho_{21.7\°C}=745.207 kg/m^{3} (6)

Now we can calculate the mass of gasoline at this temperature:

m_{2}=\rho_{21.7\°C}V (7)

m_{2}=(745.207 kg/m^{3})(0.0323 m^{3}) (8)

m_{2}=24.070 kg (9)

And finally calculate the mass difference \Delta m:

\Delta m=m_{2}-m_{1}=24.070 kg-23.579 kg (10)

\Delta m=0.4911 kg (11) This is the extra mass of gasoline

6 0
3 years ago
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