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3 years ago

WILL UPVOTE! MULTIPLE CHOICE!

1 answer:

6 0

1. A. The SI unit for current is the ampere.
2. C. The unit for resistance = ohm.
3. B. EMF is measured in volts.
4. B. Electric current is the flow of charged particles, i.e. electrons.
5. B or C. All other answers are metals.
6. C. The dimensions of a material don't affect its resistance.
7. D. Ohm's law: current = voltage / resistance, 12/4 = 3.
8. B. Batteries transform chemical energy into electrical energy.
9. A. Metals are generally good conductors.

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Which of the following could you do to increase the strength of an electromagnet?

Ann [662]

Wrap around a metal with wire instead of using wire alone.

8 0

3 years ago

Four point charges, each of magnitude 2.38 µC, are placed at the corners of a square 75.2 cm on a side. If three of the charges

poizon [28]

Answer:

The Electric Force on Negative Charge is 2.968 N

Explanation:

charge on each corner, q = 2.38 micro coulomb

Side of square, a = 75.2 cm

Coulombic constant, K = 8.98755 x 10^9 Nm²/C²

sides of the square are A,B,C and D

and all sides of a square are equal so

AB = BC = CD = DA = 75.2 cm = 0.752 m

Diagonal, AC = BD = 1.414 x 0.752 = 1.06 m

Electric field at D due to charge at A

EA= Kq÷AB^2

= 8.98755×10^9 × 9.87×10^-6 ÷ 0.752^2

EA= 156863.82 N/C

Similarly Electric field at D due to charge C

EC=Kq÷CD^2

= 8.98755×10^9 ×9.87×10^-6 ÷ 0.752^2

EC= 156863.82 N/C

Electric field at D due to charge at BB

EB=Kq÷BD^2

EB=8.98755×10^9 × 9.87×10^-6 ÷ 1.06^2

EB=78949.01 N/C

Resolve the compoents

Ex = EA + EB cos 45

Ex = 156863.82 + 78949.01 x 0.707

Ex = 212689.2 N/C

Ey = EC + EB Sin 45

Ey = 156863.82 + 78949.01 x 0.707

Ey = 212689.2 N/C

The resultant electric field is

E = 1.414 x 212689.2 = 300787.95 N/C

the electric force on the negative charge is

F = q x E

F = 9.87 x 10^-6 x 300787.95

F = 2.968 N

7 0

2 years ago

Zeros are always considered significant digits when they are to the left of the decimal point

maksim [4K]

Answer:

Zeros to the left of a decimal can be insignificant place holders, such as in 0.043 (two significant figures).

They can be significant if they are between two digits who themselves are significant, such as in 101.000 (three significant figures).

In the case of a number like 1,000 we can see there is only one significant figure. The zero digits are not between sigfigs.

7 0

3 years ago

2. A Plate 0.02 mm distance from a fixed Plate moves at a velocity Of 0.6mls and requires a force of 1.962 N Per unit area to ma

Marizza181 [45]

Answer:

6.54 × 10⁻⁵ Pa-s

Explanation:

Since the shear force, F = μAu/y where μ = viscosity of fluid between plates, A = area of plates, u = velocity of fluid = 0.6 m/s and y = separation of plates = 0.02 mm = 2 × 10⁻⁵ m

Since F = μAu/y

F/A = μu/y where F/A = force per unit area

Since we are given force per unit area, F/A = 1.962 N per unit area = 1.962 N/m²

So, μ = F/A ÷ u/y

substituting the values of the variables into the equation, we have

μ = F/A ÷ u/y

μ = 1.962 N/m² ÷ 0.6 m/s/2 × 10⁻⁵ m

μ = 1.962 N/m² ÷ 0.3 × 10⁵ /s

μ = 6.54 × 10⁻⁵ Ns/m²

μ = 6.54 × 10⁻⁵ Pa-s

5 0

3 years ago

A student standing on the ground throws a ball straight up. The ball leaves the student's hand with a speed of 16.0 when the han

slava [35]

There are mistakes in the question as the unit of speed and height is not mention here.The correct question is here

A student standing on the ground throws a ball straight up. The ball leaves the student's hand with a speed of 16.0m/s when the hand is 1.80m above the ground.How long is the ball in the air before it hits the ground? (The student moves her hand out of the way.)

Answer:

t=3.37s

Explanation:

Given Data

As we have taken hand at origin and positive upward

So given data are

$y_{i}=0m\\y_{f}=-1.80m\\v_{i}=16.0m/s\\a=g=9.8m/s^{2}$

To find

time taken by the ball before it hits the ground

Solution

By using the common kinematic equation

$y_{f}=y_{i}+v_{i}t+0.5at^{2}$

Put the given values and find for t

$-1.80=0+16.0t+(0.5*(-9.8)t^{2} )\\-1.80=16.0t-4.9t^{2}\\ 4.9t^{2}-16.0t-1.80=0$

Apply quadratic formula to solve for t

$t=\frac{-(-16.0)+\sqrt{(-16)^{2}+4(4.9)(-1.80)} }{2(4.9)}\\ t=3.37s$

4 0

3 years ago