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A car is moving at a constant speed of 14 m/s when the driver presses down on the gas pedal and accelerates for 14 s with an acc

Vinil7 [7]

acceleration of car is 1.8 m/s^2

time = 14 s

initial speed = 14 m/s

so the final speed is calculated by

$v_f = v_i + at$

$v_f = 14 + 14 * 1.8$

$v_f = 39.2 m/s$

so the total distance moved in this interval of time is

$d = \frac{v_f + v_i}{2}* t$

$d = \frac{39.2 + 14}{2}* 14$

$d = 372.4 m$

now the average speed is given as

$v = \frac{d}{t}$

$v = \frac{372.4}{14}$

$v = 26.6 m/s$

so the average speed will be 26.6 m/s

7 0

3 years ago

Which is an example of a fission reaction? Check all that apply.

Sergeu [11.5K]

Answer:

Check Explanation

The fission reactions include

239 Pu + n → Ce + Kr + 2n

And

295 Am + in → 154 La + 95 Sr + 3 n

Explanation:

A fission reaction is a radioactive reaction in which an atom with a heavy nuclei splits into atoms with smaller or lighter nuclei usually brought about by the attack of a fundamental particle and accompanied by the release of some fundamental particles (neutrons mostly) and energy.

Although, the reactions to be examined aren't totally clear, we can still guess which element is which and know which of the reactions has a heavier nuclei splitting into smaller ones.

1) H + H → He + 2n

Two hydrogen atoms combine to give an helium atom and release neutrons too, showing that here, smaller molecules combine to form a bigger one. Hence, this isn't a fission reaction, rather, it's a fusion reaction.

2) 239 Pu + n → Ce + Kr + 2n

Here, Pu (Plutonium, atomic mass 239), a heavy nuclei that splits into smaller nuclei, Ce (Cerium, atomic mass 140) and Kr (Krypton, atomic mass 84) together with some neutrons to fit the definition of a fission reaction. Hence, this reaction is a fission reaction.

3) 295 Am + n → 154 La + 95 Sr + 3 n

Here, Pu (Americium, atomic mass 295), a heavy nuclei that splits into smaller nuclei, Ce (Lamthanium, atomic mass 154) and Sr (Strontium, atomic mass 95) together with some neutrons to fit the definition of a fission reaction. Hence, this reaction is a fission reaction.

4) 13C + H → 14N

Carbon 13 combines with a hydrogen element to mutate and give nitrogen-14, a heavier nuclei, showing all signs of a nuclear fission and not fission.

Hope this Helps!!!

4 0

3 years ago

A force of 120 N is exerted on a 40 kg container which sits on a floor. If the frictional force between floor and container is 8

harkovskaia [24]

Answer:

Magnitude is 144N .

Explanation:

a²+b²=c²

120N²+80N²=c²