A raspberry has a red color because it _____ red light. A. emits B. reflects C. absorbs D. transmits

Which of the following statements is/are true? Check all that apply. A. A potential energy function can be specified for a conse

Otrada [13]

Answer:

A. A potential energy function can be specified for a conservative force.

TRUE

because there is no loss of energy in conservative type of forces.

B. A nonconservative force permits a two-way conversion between kinetic and potential energies.

FALSE

It is not true because energy is not conserved in non-conservative forces.

C. The work done by a nonconservative force depends on the path taken.

TRUE

It depends on total path length while in conservative it only depends on initial and final state

D. A potential energy function can be specified for a nonconservative force.

FALSE

Since energy is not stored in non-conservative forces so it is not defined for non conservative forces

E. A conservative force permits a two-way conversion between kinetic and potential energies.

TRUE

Work done against conservative forces is stored in form of potential energy so it is possible to have two way conversion.

F. The work done by a conservative force depends on the path taken.

FALSE

Conservative force work depends only on initial and final state

5 0

4 years ago

Which of the following pairings are more likely to be held together with the strong nuclear force?

aivan3 [116]

Which of the following pairings are more likely to be held together with the strong nuclear force

Explanation:

1.What does a strong nuclear force do in an atom? It repels electrons from other electrons. It repels protons from other protons. It attracts protons and neutrons.

2.The chain reaction requires both the release of neutrons from fissile isotopes undergoing nuclear fission and the subsequent absorption of some of these neutrons in fissile isotopes.

3.The strong nuclear force holds most ordinary matter together because it confines quarks into hadron particles such as the proton and neutron. In addition, the strong force binds these neutrons and protons to create atomic nuclei.

8 0

3 years ago

A block with mass of 10 kg is on a frictionless surface. One hand on the left side of the block is pushing it to the right. A se

igomit [66]

Answer:

$W_2=-12J$

Explanation:

The work of force 2 will be given by the vectorial equation $W_2=F_2.d$ . We know the value of $F_1$ and have information about its movement, which relates to the net force $F=F_1+F_2$ .

About this movement we can obtain the acceleration using the equation $v_f^2=v_i^2+2ad$ . Since it departs from rest we have $a=\frac{v_f^2}{2d}$ .

And then using Newton's 2dn Law we can obtain the net force F=ma, thus we will have $F_2=F-F_1=ma-F1=\frac{mv_f^2}{2d}-F_1$

And we had the work done by force 2 as:

$W_2=F_2.d=\frac{mv_f^2}{2}-F_1d$

(The sign will be given algebraically since we take positive the direction to the right.)

With our values:

$W_2=\frac{(10kg)(2m/s)^2}{2}-(8N)(4m)=-12J$

Another (shorter but maybe less intuitive way for someone who is learning) way of doing this would have been to say that the work done by both forces would be equal to the variation of kinetic energy:

$W_1+W_2=K_f-K_i=K_f=\frac{mv_f^2}{2}$

Which leads us to the previous equation straightforwardly.

6 0

3 years ago

A 330 kg piano slides 3.6 m down a 28o incline and is kept from accelerating by a man who is pushing back on it parallel to the

e-lub [12.9K]

Answer:

a. 652.68N

b. -2349.65J

c. -3116.12J

d. 5465.77J

e. Zero

Explanation:

a. According to equilibrium of forces, the force of gravity is equal to the sum of the frictional force and force exerted by the man in the opposite direction (since they're both resistant forces).

Fg = Fm + Fr

Fm = Fg - Fr

Fm = mgsin(28°) - umgcos(28°)

u = coefficient of frictional force.

Fm = 330*9.8*sin28 - 0.4*330*9.8*cos28

Fm = 1518.27 - 865.59

Fm = 652.68N

b. Work done by man is:

Wm = -Fm * d

Wm = -652.68 * 3.6

Wm = -2349.65J

c. Work done by friction force:

W(Fr) = -Fr * d

W(Fr) = -865.59 * 3.6

W(Fr) = -3116.12J

d. Work done by gravity:

Wg = Fg * d

Wg = 1518.27 * 3. 6

Wg = 5465.77J

e. Net work done on the piano is:

Work done by friction + work done by gravity + work done by man

= -3116.12 + 5464.77 + (-2349.65)

= 0J

7 0

3 years ago

In the late 19th century, great interest was directed toward the study of electrical discharges in gases and the nature of so-ca

gizmo_the_mogwai [7]

Answer:

A) He finds the same value of q / m for different materials , B) y = ½ (q / m) E L² / v₀ₓ² , C) v = E / B , D) B = 2.13 10⁻⁶ T, E) For the first part I have two off-center points., For the second part I can center one point but the other is off center

Therefore the third statement is correct

Explanation:

Part A

Thomson's experiments are the first proof that the atoms that until now were considered indivisible were constituted by different elements, in these experiments Thomson himself the ratio q / m of several cathodes and always found the same value, which allowed to establish that In atoms there are two types of particles, some of which are mobile and others are still.

When examining his statements the correct one is: He finds the same value of q / m for different materials

Part B

For this part let's use Newton's second law

F = ma

q E = m a

a = q / m E

We use the kinematic relationship

y = voy t - ½ to t²

x = v₀ₓ t

The initial vertical velocity of electrons is zero

y = ½ a (x / v₀ₓ)²

We replace

y = ½ (q / m) E L² / v₀ₓ²

Part C

If there is no deflection, the electric and magnetic forces are the same and in the opposite direction

Fm = Fe

q v B = q E

v = E / B

Part D

We replace

y = ½ (q / m) E L² / (E / B)²

y = ½ (q / m) L² B² / E

If we do not want any deflection the magnetic field has to return the electrons the amount that they lower y = -4.12 cm

-4.12 10⁻² = ½ q / m 0.12² B² / 1.1 10³

-16.97 10⁻⁴ = 6.54 10⁻³ B² q / m

B² = -2.59 10⁻¹ q / m

q / m = -1.758 10¹¹ C/ kg

B = √ 0.259 1.758 10¹¹ = √ 4.55 10⁻¹²

B = 2.13 10⁻⁶ T

Part E

As the charge that the two particles is different

For the first part I have two off-center points.

For the second part I can center one point but the other is off center

Therefore the third statement is correct

8 0

3 years ago