 Lv 1166 points

# Jen

Questions6
• ### Help, somebody help me as I don't know what I did wrong?

The ray makes an angle of θ1 = 16 degrees with respect to the normal of the surface. The index of the air is n1 = 1 while water is n2 = 1.33. Write an expression for the reflection angle ψ, with respect to the surface.

I don't know what that would be as 74d or theta

They are requiring a symbol but it's not degree sign or theta.

They give you alpha, beta, theta, theta1, a, d, g, h, i, j,k,m, P, S, t

Don't know what it could be

or is it not 74 degrees?

• ### Help, somebody help me as I don't know what I did wrong?

The ray makes an angle of θ1 = 16 degrees with respect to the normal of the surface. The index of the air is n1 = 1 while water is n2 = 1.33. Write an expression for the reflection angle ψ, with respect to the surface.

I don't know what that would be as 74d or theta

They are requiring a symbol but it's not degree sign or theta.

They give you alpha, beta, theta, theta1, a, d, g, h, i, j,k,m, P, S, t

Don't know what it could be

or is it not 74 degrees?

• ### Electric field and forces help, pls?

Find the magnitude of the net Coulomb force, in newtons, on the charge q in the figure, given that q = 0.85 μC, qa = 1.5 μC, qb = -4.3 μC, qc = -5.6 μC, and qd = 1.5 μC. The square is 45 cm on a side.

I tried several different ways of solving this problem and none of the answers are correct. I am at a lose.

I used coulomb law

F=k(Q1Q2/r^2)

my answer came out to be 0.314

Wrong

My next answer came out 0.246

wrong again

• ### What is i dot B?

I have not been taught about how to do these equation but now I am expected to know with no background knowledge on dot product.

So I don't understand how do I get the answers for...

What is i dot B?

What is j dot B?

What (3i-j)dot B?

What is (B/B)dot B?

Do you use MagB(CosthetaB)? I am reading through a confusing textbook for answers that don't look remotely similar. Help, please.

• ### I don't get it?

Select all cases where the sum of the vectors is zero.

How am I suppose to know which are the cases where the sum of the vectors is zero from the graph provided.

I'm down to one try left. I need all the help I can get. Please enlighten me.

I thought it would be 4, 2

I thought maybe 4,1, 2

or 3, 2

But there are all wrong

• ### Need some help math?

In the diagram, the dashed lines are parallel to the x axis. The magnitudes of the vectors are A = 12, and F = 20.8. The angles, in degrees, are θA = 30.0, and θF = 30.0. In this problem, you will be asked to calculate the value of a variety of scalar (dot) products. And the question is, what is A*F?

A dot F=12(20.8)cos(60)=124.8

Said I was off by 1/2

But what am I doing wrong?

Please if anyone can, walk me through this.

• ### Redox reaction?

There are 3 equation

1) 2ZnS(s)+3O2(g)-->2ZnO(s)+2SO2(g)

2) Ag+(aq)+Br-(aq)-->AgBr(s)

3) 10H+(aq)+SO42-(aq)+8I-(aq)-->4I2(s)+H2S(g)+4H2O(l)

classify each reactant in the chemical equations as an Oxidizing agent, Reduced agent, or neither.

ZnS

O2

Ag+

Br-

SO4^2-

I-

H+

Calculate the increase or decrease in oxidation state for ea. element listed as it changes from a reactant to a product.(Use a negative sign to show a decrease in oxidation state.)

Sulfur, beginning in the reactant ZnS

Bromine, beginning in the reactant Br-

Iodine, beginning in reactant I-

Sulfur, beginning in the reactant SO4^2-

I have been unsuccessful for over 2weeks, someone, please explain it to me.

• ### Static Equilibrium?

A solid bar of length L has a mass m 1. The bar is fastened by a pivot at one end to a wall which is at an angle θ with respect to the horizontal. The bar is held horizontally by a vertical cord that is fastened to the bar at a distance x from the wall. A mass m 2 is suspended from the free end of the bar.

Find the tension in the cord.

1.T=(m1+1/2m2) (L/x)g

2.T= (m1+m2)gcosθ

3.T=(m1+1/2m2) (L/x)gcosθ

4.T= (m1+m2)gsinθ

5.T= 0

6.T=(m1+1/2m2) (L/x)gsinθ

7.T=(1/2m1+m2) (L/x)gcosθ

8.T= (m1+m2)(L/x)(g2)

9.T=(1/2m1+m2) (L/x)gsinθ

10.T=(1/2m1+m2) (L/x)g

My best guess was 7.

I'm so confused and I'm not sure what I'm looking at.

• ### What isKf/Ki,the ratio of the final to the ini-tial kinetic energy of the system of two balls?

A ball of mass1 M collides head-on and in elastically with a ball of mass2 3M .Before the collision, the ball of mass M is moving to the right at speed v01 and the ball of mass 3M is moving to the left at the same speedv02.

After the collision, the ball of mass 3Mismoving to the left at speedv02.

You first need to calculate the velocity of the ball of mass M after the collision, provided it recoils to the left.

Vf=(m1v1+m2v2)/m1+m2 I assume 1 but its not and its not 1/2 I don't understand.