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2 years ago

The temperature of the liquid in a container decreases as the liquid evaporates. Use kinetic theory to explain why.

Physics

1 answer:

melisa1 [442]2 years ago

6 0

Answer:

Temperature decreases because the number of collision of the molecules decreases as they escape or evaporate. Molecules are in constant motion. Increase in temperature leads to increase in average kinetic energy of the molecules.

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Give two ways of reversing the direction of the forces on the coil in the electric motor?

nikklg [1K]

Answer:

Interchanging the poles of the magnet

Reversing the direction of the applied current

Explanation:

The working of the electric motor is associated with Fleming's left-hand rule.
It states that if a current-carrying conductor is placed inside a magnetic field, it experiences a force in the direction perpendicular to the direction of the electric current and magnetic field.
These three physical quantities are placed in a mutually perpendicular direction.
So, in order to reverse the direction of force, you have to either change the direction of the current or magnetic field.

4 0

2 years ago

The angle θ is slowly increased. Write an expression for the angle at which the block begins to move in terms of μs.

Reika [66]

Answer:

$tan \theta = \mu_s$

Explanation:

An object is at rest along a slope if the net force acting on it is zero. The equation of the forces along the direction parallel to the slope is:

$mg sin \theta - \mu_s R =0$ (1)

where

$mg sin \theta$ is the component of the weight parallel to the slope, with m being the mass of the object, g the acceleration of gravity, $\theta$ the angle of the slope

$\mu_s R$ is the frictional force, with $\mu_s$ being the coefficient of friction and R the normal reaction of the incline

The equation of the forces along the direction perpendicular to the slope is

$R-mg cos \theta = 0$

where

R is the normal reaction

$mg cos \theta$ is the component of the weight perpendicular to the slope

Solving for R,

$R=mg cos \theta$

And substituting into (1)

$mg sin \theta - \mu_s mg cos \theta = 0$

Re-arranging the equation,

$sin \theta = \mu_s cos \theta\\\rightarrow tan \theta = \mu_s$

This the condition at which the equilibrium holds: when the tangent of the angle becomes larger than the value of $\mu_s$ , the force of friction is no longer able to balance the component of the weight parallel to the slope, and so the object starts sliding down.

4 0

2 years ago

The submarine sends out a sound wave that returns in 1.08 seconds. If this sound wave has a frequency of 2.50 × 106 Hz and a wav

Shtirlitz [24]

Answer:

1620

Explanation:

....................

5 0

2 years ago

a proton is moving horizontally at 7.9 x 10^5 m/s. It passes through a vertical magnetic field that points downward. In which di

blondinia [14]

There are four key characteristics of the magnetic force on a moving charge.

First, Its magnitude is proportional to the magnitude of the charge.
Second, the magnitude of the force is also proportional
Third, the magnetic force depends on the particle’s
velocity.
Fourth, we find by experiment that the magnetic force $\vec{F}$ does not have the same direction as the magnetic field $\vec{F}$ but instead is always perpendicular to both $\vec{B}$ and the velocity $\vec{v}$

So, in a mathematical language this is given by:

$\vec{F}=q\vec{v} \times \vec{B}$

So, this is a cross product. Therefore, applying the Right-hand rule:

The answer is:

<span>D. to the left of its velocity.

Explaining this in other words:

"The force </span> $\vec{F}$ is directed into the plane of the paper, so this is the direction of the proton"

7 0

2 years ago

A skydiver is using wind to land on a target that is 50 m away horizontally. The skydiver starts from a height of 70 m and is fa

elena55 [62]

Answer:

Answer:

15.67 seconds

Explanation:

Using first equation of Motion

Final Velocity= Initial Velocity + (Acceleration * Time)

v= u + at

v=3

u=50

a= - 4 (negative acceleration or deceleration)

3= 50 +( -4 * t)

-47/-4 = t

Time = 15.67 seconds

6 0

2 years ago