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3 years ago

Why can we see a red shirt

2 answers:

8 0

The colours we see are the wavelengths that are reflected or transmitted. For example, a red shirt looks red because the dye molecules in the fabric have absorbed the wavelengths of light from the violet/blue end of the spectrum.

natita [175]3 years ago

3 0

You might be interested in

a student attaches a 0.5 kg object to a 0.7 m string and rotates the object around her head and parallel to the ground. how much

Marina CMI [18]

The object would have a centripetal acceleration a of

a = (12 m/s)² / (0.7 m) ≈ 205.714 m/s²

so that the required tension in the string would be

T = (0.5 kg) a ≈ 102.857 N ≈ 100 N

(rounding to 1 significant digit)

3 0

3 years ago

To initiate a nuclear reaction, an experimental nuclear physicist wants to shoot a proton into a 5.50-fm-diameter 12C nucleus. T

Fantom [35]

Answer:

$V_1= 3.4*10^7m/s$

Explanation:

From the question we are told that

Nucleus diameter $d=5.50-fm$

a 12C nucleus

Required kinetic energy $K=2.30 MeV$

Generally initial speed of proton must be determined,applying the law of conservation of energy we have

$K_2 +U_2=K_1+U_1$

where

$K_1$ =initial kinetic energy

$K_2$ =final kinetic energy

$U_1$ =initial electric potential

$U_2$ =final electric potential

mathematically

$U_2 = \frac{Kq_pq_c}{r_2}$

where

$r_f$ =distance b/w charges

$q_c$ =nucleus charge $=6(1.6*10^-^1^9C)$

$K$ =constant

$q_p$ =proton charge

Generally kinetic energy is know as

$K=\frac{1}{2} mv^2$

Therefore

$U_2 = \frac{Kq_pq_c}{r_2} + K_2=\frac{1}{2} mv_1^2 +U_1$

Generally equation for radius is $d/2$

Mathematically solving for radius of nucleus

$R=(\frac{5.50}{2}) (\frac{1*10^-^1^5m}{1fm})$

$R=2.75*10^-^1^5m$

Generally we can easily solving mathematically substitute into v_1

$q_p$ $=6(1.6*10^-^1^9C)$

$K_1=9.0*10^9 N-m^2/C^2$

$U_1= 0$

$R=2.75*10^-^1^5m$

$K=2.30 MeV$

$m= 1.67*10^-^2^7kg$

$V_1= (\frac{2}{1.67*10^-^2^7kg})^1^/^2 (\frac{(9.0*10^9 N-m^2/C^2)*(6(1.6*10^-^1^9C)(1.6*10^-^1^9C)}{2.75*10^-^1^5m+2.30 MeV(\frac{1.6*10^-^1^3 J}{1 MeV}) }$

$V_1= 3.4*10^7m/s$

Therefore the proton must be fired out with a speed of $V_1= 3.4*10^7m/s$

8 0

3 years ago

True or False. A projectile is an object that once set in motion, continues in motion by its own inertia.

bazaltina [42]

The answer is true.

5 0

3 years ago

Read 2 more answers

A 7.0 mm -diameter copper ball is charged to 40 nC. What fraction of its electrons have been removed? The density of copper is 8

mylen [45]

Answer:

$f = 2.6 \times 10^{-13}$

Explanation:

Let the mass of copper ball is "m" gram

now the total number of copper atom present in the ball is given as

$N = \frac{m}{29} \times 6.02 \times 10^{23}$

now the total number of electrons in one copper atom is 29

so total number of electrons in given sample of copper ball is

$N_e = m(6.02 \times 10^{29})$

now diameter of the ball is 7.0 mm

density of the ball = $8900 kg/m^3$

now we have

$m = (\frac{4}{3}\pi r^3)(8900)$

$m = (\frac{4}{3}\pi(\frac{0.007}{2})^3)(8900)$

$m = 1.6 gram$

now we have

$N_e = 9.63 \times 10^{23}$

now the charge on the copper ball is 40 nC

so the number of electrons removed

$Q = ne$

$40 \times 10^{-9} = n(1.6 \times 10^{-19}$

$n = 2.5 \times 10^{11}$

so the fraction of number of electrons removed is given as

$f = \frac{n}{N_e}$

$f = \frac{2.5 \times 10^{11}}{9.63 \times 10^{23}}$

$f = 2.6 \times 10^{-13}$

7 0

4 years ago

If a polythene rod is rubbed with a dry cloth, what kind of charge would it gain? A) positive, due to extra protons. B) positive

Likurg_2 [28]

Answer:

D) negative, due to extra electrons.

Explanation:

The charge that would be gained will be negative charges due to extra electrons.

Electrons are usually lost or gained by bodies that comes in contact with one another.

They occupy the orbital space in an atom and are not strongly held by forces within the atom.

Protons cannot be lost in such manner. They occupy the nucleus and are bounded by strong chemical forces within it.

The polythene and rods are both made up of chemical substances whose units called atoms are made up of subatomic particles of protons, neutrons and electrons. As with all kinds of matter, there would be pool of free electrons round them that can easily be rubbed off due to the weak attractive forces binding them in the atomic sphere.

When the polythene and rods are rubbed, there would be a loss of electrons and the gaining body, polythene becomes negatively charged.

6 0

3 years ago