An observation of the red shift of galaxies suggestst that the universe is

1 answer:

3 0

A) Expanding. We know this because it has a similar effect with sound. When a car goes by the pitch gets deeper and deeper. It's because you're receiving less waves. Same thing for light but instead of a pitch it's light, and the farther spread the waves - the redder, the closer and more contracted - the bluer

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A magnetic force can act on an electron even when it A) is at rest B) moves parallel to magnetic field lines C) both of these D)

Kobotan [32]

Answer: A)

Explanation: when an electron is placed in a magnetic field, it experiences a force.

This force is given below as

F=qvB*sinθ

F = force experienced by charge.

q = magnitude of electronic charge

v = speed of electron

B= strength of magnetic field

θ = angle between magnetic field and velocity.

What defines the force exerted on the charge is the angle between the field and it velocity.

If magnetic field is parallel to velocity, then it means that θ=0° which means sin 0 = 0, which means

F = qvB * 0 = 0.

The charge being at rest has nothing to do with the angle between magnetic field strength and velocity.

3 0

3 years ago

Air in the atmosphere is heated by the ground this warm air then rises and cooler air falls this is an example of what type of p

Alona [7]

The answer for both is ‘B’

8 0

2 years ago

A curve in a stretch of highway has radius R. The road is not banked in any way. The coefficient of static friction between the

adelina 88 [10]

Answer:

maximum possible velocity = $\sqrt{ugR}$

Explanation:

centripetal acceleration when the car is going in the circle must be less than the maximum friction for the car to not slip.

centripetal acceleration $\frac{mv^{2}}{r}$

where v is the velocity of car and r is the radius of circle

maximum friction = umg

where u is the coefficient of static friction.

therefore $umg\geq \frac{mv^{2}}{R}$

therefore maximum possible velocity = $\sqrt{ugR}$

6 0

3 years ago

Where will water evaporate from?

Elodia [21]

Water will evaporate from any water source and life forms. The answer is letter C. An application of heat into water will cause the water to evaporate. This is because the intermolecular forces of attraction of water can be broken by sufficient energy application.

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2 years ago

A sample of ore containing radioactive strontium 38Sr90 has an activity of 8.2 × 105 Bq. The atomic mass of strontium is 89.908

ahrayia [7]

From the activity values and the decay constant, the mass of of Strontium in the sample is:

$1.62 × 10^{-7}g$