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4 years ago

13. Predict whether each of the following will sink or float:

1 answer:

3 0

A. The pencil led would float in the corn syrup because it’s density is less than the water. B. The acrylic would sink in water because it has more density than the water. C. The polyethylene would sink because it’s density is less than the water

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Which one of the following statements concerning emf is true?

Andrej [43]

Answer:

C) Emf is the force exerted on a single charge to move it from one terminal to the other of an emf device.

Explanation:

Electromotive force, abbreviation E or emf, electrical energy per unit supplied from an energy source, such as an electrical generator or a battery. In the engine or battery, electricity is transformed from one source to another as the device works on the electrical charge that is passed within itself.

In physics it is defined as Work done by a cell or battery in moving a unit charge from its one terminal to the other, against the potential.

Hence C is correct

3 0

3 years ago

A tank whose bottom is a mirror is filled with water to a depth of 20.0 cm. A small fish floats motionless 7.0 cm under the surf

liberstina [14]

Answer:

The apparent depth of (a) the fish is 5.3 cm and (b) the image of the fish is 24.8 cm.

Explanation:

According to the following equation:

$\frac{n_{w} }{s} +\frac{n_{a} }{s'} = \frac{n_{a}- n_{w}}{R_{c} } \\$

where nw and na is the refractive indices of water (1.33) and air (1.00) respectively; s is the depth of the fish below the surface of the water; s' is the apparent depth of the fish from normal incidence and Rc is the radius of curvature of the mirror at the bottom of the tank.

Note that the bottom of the tank is assumed to be a flat mirror, therefore the radius of curvature is very large (R⇒∞).

Therefore, the above equation can be expressed as:

$\frac{n_{w}}{s} +\frac{n_{a}}{s'}=0$

Now we can solve for the apparent depth of the fish.

(a) $s'=-(\frac{n_{a}}{n_{w}})x s$ (Make s' subject of the formula from the above equation)

$s'=(\frac{1.00}{1.33} )x7cm$

∴ $s'=5.3 cm.$

(b) The motionless fish floats 13 cm above the mirror, therefore the image of the fish will be situated at 13 + 20 =33 cm away from the real fish.

Therefore, s = 33 cm

$s'=-(\frac{n_{a}}{n_{w}})x s$

$s'=(\frac{1.00}{1.33} )x 33 cm$

$s'=24.8 cm.$

NB: Here, it is assumed that the water is pure, as impurities may alter the refractive index of water.

8 0

4 years ago

A cart loaded with bricks has a total mass of 20.4 kg and is pulled at constant speed by a rope. The rope is inclined at 26.1 ◦

Readme [11.4K]

Answer:

Normal force, N = 154.5 N

Explanation:

Given that,

Total mass of the cart, m = 20.4 kg

Angle of inclination, $\theta=26.1^{\circ}$

Distance moved, d = 20.1 m

The coefficient of kinetic friction between ground and cart is 0.6

The value of acceleration due to gravity, $g=9.8\ m/s^2$

Let N is the normal force exerted on the cart by the floor. It is given by :

$N=mg-T\ sin\theta$

$T\ cos\theta=\mu N$

$T\ cos\theta=\mu (mg-T\ sin\theta)$

$T\ cos(26.1)=0.6 (20.4\times 9.8-T\ sin(26.1))$

T = 103.23 N

So, the normal force is :

$N=20.4\times 9.8-103.23\ sin(26.1)$

N = 154.5 N

So, the normal force exerted on the cart by the floor is 154.5 N. Hence, this is the required solution.

4 0

3 years ago

To study the properties of various particles, you can accelerate the particles with electric fields. A positron is a particle wi

Gnom [1K]

Answer:

(a) Acceleration of positron is 6.03 x 10¹³ m/s²

(b) Speed of positron after 8.70 x 10⁻⁹ s is 5.24 x 10⁵ m/s

Explanation:

Given :

Constant electric field, E = 343 N/C

Mass of positron, m = 9.1 x 10⁻³¹ kg

Charge of positron, q = +e = 1.6 x 10⁻¹⁹ C

(a) Coulomb force on the positron is determine by the relation :

F = q x E ....(1)

But, force is also equals to product of mass and acceleration. So,

F = ma .....(2)

Here a is acceleration.

From equation (1) and (2).

m x a = q x E

$a=\frac{qE}{m}$

Substitute the values of q, E and m in the above equation.

$a=\frac{1.6\times10^{-19}\times 343}{9.1\times10^{-31} }$

a = 6.03 x 10¹³ m/s²

(b) Initially, the positron is at rest, so its initial speed is zero.

The equation of motion for positron is :

v = u + at

Here v is final speed, u is initial speed and t is time.

Since, u is zero, so the equation becomes :

v = at

Substitute 8.70 x 10⁻⁹ s for t and 6.03 x 10¹³ m/s² for a in the above equation.

v = 6.03 x 10¹³ x 8.70 x 10⁻⁹ m/s

v = 5.24 x 10⁵ m/s

6 0

3 years ago

Distinguish between constructive wave interference and destructive wave interference.

Kamila [148]

Explanation:

The phenomenon of superimposing of two waves such that the resultant wave have greater, lower, or the same amplitude.

There are two conditions for the interference.

Constructive wave interference: This type of interference occurs after adding of two maxima such that the amplitude of the resulting wave is equal to the sum of the amplitudes of individual waves.

Destructive wave interference: In this type of interference, the amplitude of the resulting wave gets reduced as the crest of one wave meets with the trough of another wave.

8 0

3 years ago