What is the half-life of an isotope that decays to 25% of its original activity in 70.8 hours?

Someone pls help with only if you know correct answer!???

Roman55 [17]

Answer:

A 2.0 kg ball, A, is moving with a velocity of 5.00 m/s due west. It collides with a stationary ball, B, also with a mass of 2.0 kg. After the collision

Explanation:

5 0

2 years ago

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Describe using examples how objects can be at rest and in motion simultaneously

elena-14-01-66 [18.8K]

An object can be at rest and still be in motion because the earth is always in motion.

5 0

2 years ago

The speed of a wave in a medium is effected by____,____, and____

lisov135 [29]

$\huge\mathfrak\green{answer}$

As per as my knowledge

The speed of a wave in a medium is affected by density, wavelength and temperature :)

(Good luck on your test and mark me brainliest if this helps)

7 0

2 years ago

What is the outermost structure in a plant cell

dybincka [34]

Molecular structure of the primary cell wall in plants. Up to three strata or layers may be found in plant cell walls: The middle lamella, a layer rich in pectins. This outermost layer forms the interface between adjacent plant cells and glues them together.

5 0

2 years ago

A rock of mass 200 g is attached to a 0.75 m long string and swung in a vertical plane.

Ainat [17]

Hello!

a) Assuming this is asking for the minimum speed for the rock to make the full circle, we must find the minimum speed necessary for the rock to continue moving in a circular path when it's at the top of the circle.

At the top of the circle, we have:

- Force of gravity (downward)

*Although the rock is still connected to the string, if the rock is swinging at the minimum speed required, there will be no tension in the string.

Therefore, only the force of gravity produces the net centripetal force:

$\Sigma F = F_g\\\\F_c = F_g\\\\\frac{mv^2}{r} = mg$