Ask question

Ask question

All categories

2 years ago

5

A student has an 80 g sample of a radioactive material that has a half-life of 20 seconds. How much material will he have left a

fter 60 seconds?
A.
10 g

B.
20 g

C.
40 g

D.
5 g

1 answer:

Juliette [100K]2 years ago

7 0

The answer is C 40 g

You might be interested in

8. The legs of a young man are each 0.650 meters long. What is his maximum walking speed?

Norma-Jean [14]

Answer:

2.52 m/s

Explanation:

When the man takes a step, his foot is stationary while his body revolves around it. At the point when his body is directly above his foot, there will be no normal force at his maximum speed.

Sum of the forces in the radial direction:

∑F = ma

mg = m v² / r

g = v² / r

v = √(gr)

Given that r = 0.650 m:

v = √(9.8 m/s² × 0.650 m)

v = 2.52 m/s

8 0

2 years ago

A 1,120 kg car is travelling with a speed of 40 m/s. Find its energy.

serious [3.7K]

Answer:

this vehichle has 896,000 jules of energy

Explanation: KE=1/2mv squared, KE is Kinetic energy. m is mass and v is velocity

8 0

2 years ago

What type of energy does fresh vegetables have?

lyudmila [28]

Well it's energy comes from the sun since the sun gives it sunlight to help it grow

5 0

2 years ago

Read 2 more answers

What shape is the JET experimental fusion reactor?

Sauron [17]

Answer:

doughnut-shaped chamber called the tokamak. This is where the fusion reactions take place, within hot plasma containing deuterium and tritium atoms.

7 0

2 years ago

Read 2 more answers

If we double the frequency of a system undergoing simple harmonic motion, which of the following statements about that system ar

AnnyKZ [126]

Answer:

a. The angular frequency is doubled.

e. The period is reduced to one-half of what it was.

Explanation:

Angular frequency is given as;

ω = 2πf

$\frac{\omega _1}{f_1} = \frac{\omega _2}{f_2}$

when the frequency is doubled

$\frac{\omega _1}{f_1} = \frac{\omega _2}{(2f_1)} \\\\\omega _1 = \frac{\omega _2}{2}\\\\\omega _2 = 2\omega _1$

Thus, the angular frequency will be doubled.

Amplitude in simple harmonic motion is the maximum displacement.

Frequency is related to period in simple harmonic motion as given in the equation below;

$f = \frac{1}{T} \\\\f_1T_1= f_2T_2\\\\T_2 = \frac{f_1T_1}{f_2}$

when the frequency is doubled;

$T_2 = \frac{f_1T_1}{2f_1} \\\\T_2 = \frac{T_1}{2}$

Thus, the period will be reduced to one-half of what it was.

5 0

2 years ago