Francium decays with a half-life of 22 minutes. If we start out with 639 mg of francium, how much would remain after 2.7 hours?

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When parts of your body functions as lever systems, what part supplies the force?

For the chemical reaction C2H6 - -> C2H4 + H2 + 137kJ, the chemical energy of the reactant and the chemical energy of the products are equal. products is greater than the chemical energy of the reactant.

An elevator (mass 4100 kg) is to be designed so that the maximum acceleration is 0.0400g. what is the maximum force the motor should exert on the supporting cable? incorrect: your answer is incorrect.

How do you determine the speed or velocity of an object using a distance vs. time graph

A loop circuit has a resistance of R1 and a current of 1.9 A. The current is reduced to 1.5 A when an additional 3.1 Ω resistor is added in series with R1. What is the value of R1? Answer in units of Ω.

For glass fragments to be individualized, what must be true? A. They must fit together B. They must have the same density C. They must look the same D. They must be the same color

In what way would a digital thermometer be preferable to those from a liquid-based thermometer? Digital thermometer readings are easier to use when performing calculations.

Why does the core of the sun contain more helium and less hydrogen than the surface of the sun?

What happens to a light ray passing through the center of a lens?

A spider crawling across a table leaps onto a magazine blocking its path. The initial velocity of the spider is 0.870 m/s at an angle of 35.0° above the table, and it lands on the magazine 0.0770s after leaving the table. Ignore air resistance.