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Blizzard [7]
3 years ago
6

Which of the following statements are true? Check all that apply.

Physics
1 answer:
elena-14-01-66 [18.8K]3 years ago
8 0

Answer:

D,E,F

Explanation:

d. Earth's geographic north pole is actually a magnetic south pole.

e. The south poles of two bar magnets will repel each other.

f. The north pole of a bar magnet will attract the south pole of another bar magnet.

In a magnetic field like poles repel and unlike poles attract each other. The like poles which is south to south or north to north repel each other and the unlike poles which is north to south or south to north attract each other which makes E and F correct.

A is correct because compasses points to the North Pole when places in the Southern Hemisphere.

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10. A 12 kg load hangs from one end of a rope that passes over a small frictionless pulley. A 15 kg counterweight is suspended f
nekit [7.7K]

Answer:

6

Explanation:

6 0
3 years ago
What is Newton's second law of motion
Alexandra [31]
Newton’s second law is that the acceleration of an object is directly related to the net force and inversely related to its mass. Acceleration of an object depends on two things, force and mass.
8 0
3 years ago
When light with a wavelength of 238 nm is incident on a certain metal surface, electrons are ejected with a maximum kinetic ener
erastova [34]

Answer:

The wavelength is 173 nm.

Explanation:

This kind of phenomenon is known as photoelectric effect, it occurs when photons of light inside the metal surface and if they have the right amount of energy electrons absorb it and got expelled from the metal as photo electrons. The maximum kinetic energy of that photo electrons is given by the expression:

K_{max} =E_{photon} - \Phi (1)

With E the energy of the photon and Φ the work function of the material. The work function is a value characteristic of each material and is related with how much the electron is attached to the material, the energy of the photon is the Planck's constant (h=6.63\times10^{-34}) times the frequency of light (\nu) , then (1) is:

K_{max} =h\nu - \Phi (2)

The frequency of an electromagnetic wave is related with the wavelength (\lambda) by:

\nu=\frac{c}{\lambda} (3)

with c the velocity of light (c=3.0\times10^{8})

Using (3) on (2):

K_{max} =\frac{hc}{\lambda} - \Phi

Solving for \Phi:

\Phi=\frac{hc}{\lambda}-K_max=\frac{(6.63\times10^{-34})(3.0\times10^{8})}{238\times10^{-9}}-3.13\times10^{-19}

\Phi=5.23\times10^{-19} J

That's the work function of the metal we're dealing. So now if we want to know the wavelength to obtain the double of the kinetic energy we use:

2K_{max} =\frac{hc}{\lambda} - \Phi

Solving for \lambda:

\lambda = \frac{hc}{2K_{max}+\Phi}=\frac{(6.63\times10^{-34})(3.0\times10^{8})}{2(3.13\times10^{-19})+5.23\times10^{-19}}=1.73\times10^{-7}

\lambda=173 nm

3 0
4 years ago
A new event has been proposed for the Winter Olympics. An athlete will sprint 100 m, starting from rest, then leap onto a 20 kg
Mamont248 [21]

Answer:

3.5 m

Explanation:

Given

Mass of the bob sled , m_b = 20 kg

Mass of the girl, m = 40 kg

Speed of the girl, v = 12 m/s

Spring constant , k = 2000 N/m

Length of the ramp, L = 50 m

Angle of incline , θ = 20°

When the girl leaps on the sled , we use conservation of momentum principle

to find the speed of sled and the girl

m v + m_b (0) = (m + m_b) v_1

40 kg ×12 m/s = (20 kg + 40 kg ) v_1

v_1= 8 m/s

----------------------------------------------------------------------------

The height of the incline is ,

h = L sin 20 = 50 m  sin 20° = 17.1 m

By law of conservation of energy

(m + m_b) g h + 1/2 (m + m_b) v_1^2 = 1/2 (m +m_b) v2^2 + 1/2 k x^2

(60 kg ) ×9.8 m/s^2 ×17.1 m + 1/2 (60 kg ) (8 m/s)^2 = 1/2 (m +m_b)(0)^2 +1/2(2000 N/m) x^2

x = 3.5 m

Thus, the compression in the spring is 3.5 m

5 0
3 years ago
What happens to the air pressure inside a balloon when the balloon is squeezed to half its volume at constant temperature?
icang [17]
The answer is it doubles
7 0
3 years ago
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