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2 years ago

15

What is the name of the units that are normally used to measure energy?

1 answer:

Sati [7]2 years ago

8 0

The basic unit of energy is a joule. Kill calories measure the energy available in food.

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6. When adding vectors graphically, the direction and length of each vector must:

Tanzania [10]

Answer:

Not be changed

Option: D

<u>Explanation:</u>

The physical quantity which has both ‘magnitude and direction’ is called vector. These vectors are represented by a line and an arrow, <em>the line represent the magnitude and arrow represent the direction of the physical quantity</em>. The vectors are added and subtracted according to the direction of the vectors.

According to the vector law addition while adding vectors direction and length of the vector is not be changed.<em> If the length of the vector changed the magnitude is also changed while so, while adding vectors length must not be changed. </em>

3 0

2 years ago

he membrane that surrounds a certain type of living cell has a surface area of 6.0 x 10-9 m2 and a thickness of 1.6 x 10-8 m. As

k0ka [10]

Answer:

$1.54481175\times 10^{-12}\ C$

Explanation:

$\epsilon_0$ = Permittivity of free space = $8.85\times 10^{-12}\ F/m$

A = Area = $6\times 10^{-9}\ m^2$

d = Thickness = $1.6\times 10^{-8}\ m$

k = Dielectric constant = 5.4

V = Voltage = 86.2 mV

Charge is given by

$Q=CV\\\Rightarrow Q=k\epsilon\dfrac{A}{d}V\\\Rightarrow Q=5.4\times 8.85\times 10^{-12}\times \dfrac{6\times 10^{-9}}{1.6\times 10^{-8}}\times 86.2\times 10^{-3}\\\Rightarrow Q=1.54481175\times 10^{-12}\ C$

The charge on the outer surface is $1.54481175\times 10^{-12}\ C$

4 0

2 years ago

A beam of light strikes one face of a window pane with an angle of incidence of 30.0°. The index of refraction of the glass is 1

natka813 [3]

Answer:

(a). The angle of refraction is 19.26°.

(b). That is proved that the rays in air on either side of the glass are parallel to each other

Explanation:

Given that,

Angle of incidence = 30.0°

Index of reflection of glass = 1.52

(a). We need to calculate the angle of refraction for the ray inside the glass

Using snell's law

$\dfrac{\sin i}{\sin r}=\mu$

$\sin r=\dfrac{\sin i}{\mu}$

Put the value into the formula

$\sin r=\dfrac{\sin 30}{1.52}$

$r=\sin^{-1}(0.329)$

$r=19.26^{\circ}$

(b). We know that,

The incident ray and emerging ray is equal then the ray will be parallel.

We need to prove that the rays in air on either side of the glass are parallel to each other

Using formula for emerging ray

$\dfrac{\sin e}{\sin r}=\mu$

$\sin e=\sin r\times \mu$

Put the value into the formula

$\sin e=0.3289\times 1.52$

$e=\sin^{-1}(0.499)$

$e=29.9\approx 30^{\circ}$

So, $\sin i=\sin e$

This is proved.

Hence, (a). The angle of refraction is 19.26°.

(b). That is proved that the rays in air on either side of the glass are parallel to each other

6 0

3 years ago

A ball hits a wall horizontally at 6m/s and rebounces at 4.4m/s the ball is in contact with wall for 0.04 sec. what is the accel

Svetlanka [38]

Answer:

Acceleration (a) = 40 m/s²

Explanation:

Given:

Initial velocity (u) = 6 m/s

Final velocity (v) = 4.4 m/s

Time taken (t) = 0.04sec

Find:

Acceleration (a) = ?

Computation:

We know that,

⇒ v = u + at

⇒ a = (v - u) / t

⇒ Acceleration (a) = (4.4 - 6) / 0.04

⇒ Acceleration (a) = (-1.6) / 0.04

Acceleration (a) = 40 m/s²

8 0

3 years ago

The position x, in meters, of an object is given by the equation:

LenaWriter [7]

Answer:

The SI units of A, B and C are :

$m,\ m/s\ and\ m/s^2$

Explanation:

The position x, in meters, of an object is given by the equation:

$x=A+Bt+Ct^2$

Where

t is time in seconds

We know that the unit of x is meters, such that the units of A, Bt and $Ct^2$ must be meters. So,

$A=m$

$bt=m$

$b=\dfrac{m}{s}=m/s$

$Ct^2=m$

$C=m/s^2$

So, the SI units of A, B and C are :

$m,\ m/s\ and\ m/s^2$

So, the correct option is (B).

3 0

2 years ago