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Reil [10]
3 years ago
7

When an object has its motion changed, the cause is generally __________.

Physics
2 answers:
Eddi Din [679]3 years ago
8 0

When an object has its motion changed, the cause is generally an external force. The answer is letter A. It follows Newton’s second law of motion wherein a body is at rest and remains at rest without an external force applied to move the body.

zhuklara [117]3 years ago
8 0

A. an external force

just took the test on edge

You might be interested in
A mass M is attached to an ideal massless spring. When this system is set in motion with amplitude A, it has a period T. What is
cricket20 [7]

Answer:

<em>The period of the motion will still be equal to T.</em>

<em></em>

Explanation:

for a system with mass = M

attached to a massless spring.

If the system is set in motion with an amplitude (distance from equilibrium position) A

and has period T

The equation for the period T is given as

T = 2\pi \sqrt{\frac{M}{k} }

where k is the spring constant

If the amplitude is doubled, the distance from equilibrium position to the displacement is doubled.

Increasing the amplitude also increases the restoring force. An increase in the restoring force means the mass is now accelerated to cover more distance in the same period, so the restoring force cancels the effect of the increase in amplitude. Hence, <em>increasing the amplitude has no effect on the period of the mass and spring system.</em>

5 0
3 years ago
2. A Se lanza un electrón con rapidez inicial v0 = 1.60×106 m/s hacia el interior de un campo uniforme entre las placas paralela
Vanyuwa [196]

Answer:

A)     E = 145.6 N / C , B)  y= 2,8 10-7 m with a downward direction

C) he shape of the trajectory of the two particles is to simulate a parabola,

D)     F_{e} /F_{g} = 10³⁴

Explanation:

A) For this exercise we use Newton's second law to find the acceleration of the electron, where the force is electric

           F = m a  

           - e E = m a

          a = - e E / m

with the field directed downward, the acceleration is in the vertical upward direction.

We look for how much the electron moves with kinematics, in the x direction there is no acceleration,

x axis (parallel to plates)

           x = v₀ t

           t = x / v₀

y axis (perpendicular to plates)

          y = y₀ + v_{oy} t + ½ a t²

Let's take the zero of the system in the middle of the plates y₀ = 0, also the initial vertical velocity is zero (v_{oy} = 0) the width of the plate is known

          y = ½ a t²

we substitute

         y = ½ (e E /m)  (x / v₀)²

         y = ½ e x2 /m v₀²   E

we look for the electric field

        E = 2 m y v₀² / e x²

where to use this expression the length and width of the condenser must be known, suppose that the length is x = l = 1 cm = 1 10⁻² m and the width is y = 0.5 mm = 0.5 10⁻³ m

let's calculate

         E = 2  9.1 10⁻³¹ 0.5 10⁻³ (1.6 10⁶)² / (1.6 10⁻¹⁹ (1 10⁻²)²)

         E = 145.6 N / C

B) The electron is exchanged for a proton

Let's look for the vertical displacement, in this case as the proton has a positive charge it moves towards the bottom of the plates

          y = ½ e x² / m v₀² E

          y = ½ 1.6 10⁻¹⁹ 1 10⁻⁴ / (1.67 10⁻²⁷ (1.6 10⁶)²   145.6

          y = 28.4375 10⁻⁸ m

since the distance between the plates is 0.5 10-3 m, the proton passes the condensate because its deflection is very small

In summary, its displacement is y= 2,8 10-7 m and with a downward direction (the same direction of the electric field)

C) The shape of the trajectory of the two particles is to simulate a parabola, but one for having a negative charge (electron) the force is upwards and the other for having a positive charge (proton) the trajectory is downwards

D) The force of gravity

           F_{g} = G m M / R²

electron

          Between the electron and the positive charges of the conducting plate

           F_{g}= 6.67 10⁻¹¹ 1.67 10⁻²⁷ 9.1 10⁻³¹ / (0.5 10⁻³)²

           F_{g} = 4.1 10⁻⁵¹ N

           

electric force

           F_{e} = -e E

           F_{e} = - 1.6 10⁻¹⁹ 145.6

           F_{e} = 2.3 10⁻¹⁷ N

let's look for the reason between these two forces

         F_{e} / F_{g} = 2.3 10⁻¹⁷ / 4.1 10⁻⁵¹

          F_{e} /F_{g} = 10³⁴

We see that the electric force is many orders of magnitude higher than the gravitational force.

5 0
3 years ago
A protein molecule in an electrophoresis gel has a negative charge.The exact charge depends on the pH of the solution, but 30 ex
Ad libitum [116K]

Answer:

The magnitude of the electric force on a protein with this charge is 7.2\times10^{-15}\ N

Explanation:

Given that,

Electric field = 1500 N/C

Charge = 30 e

We need to calculate the magnitude of the electric force on a protein with this charge

Using formula of electrostatic force

F=Eq

Where, F = force

E = electric field

q = charge

Put the value into the formula

F=1500\times30\times1.6\times10^{-19}

F=7.2\times10^{-15}\ N

Hence, The magnitude of the electric force on a protein with this charge is 7.2\times10^{-15}\ N

6 0
3 years ago
In a 49 s interval, 595 hailstones strike a glass window of an area of 0.954 m at an angle of 25° to the window surface. Each ha
eduard

Average  force on the window: 0.32 N

Explanation:

The average force exerted on the window is given by Newton's second law

F=\frac{\Delta p}{\Delta t}

where

\Delta p is the net change in momentum of the hailstones in a time interval of \Delta t

In order to find the change in momentum, we have to consider only the component of the hailstone's momentum perpendicular to the window, therefore:

p_i =m u sin \theta is the initial momentum of one hailstone, with

m = 7 g = 0.007 kg is the mass

u=4.5 m/s is the initial speed

\theta=25^{\circ} is the angle with the window

The final momentum is

p_f = mv sin \theta

where

v = 4.5 m/s is the final speed (the  collision is elastic so the speed is equal, while the direction changes)

\theta=-25^{\circ} (after the rebound, the direction has changed)

So the change in momentum of 1 hailstone is

\Delta p = mv sin(-25^{\circ})-mu sin(25^{\circ})=-2mu sin(25^{\circ})=-0.0266 kg m/s

We are interested only in the magnitude, so

\Delta p = 0.0266 kg m/s

There are 595 hailstones hitting the window in 49 s, so the total change in momentum is

\Delta p = 595\cdot 0.0266 = 15.8 kg m/s

And therefore, the average force on the window is

F=\frac{\Delta p}{\Delta t}=\frac{15.8}{49}=0.32 N

Learn more about  force:

brainly.com/question/8459017

brainly.com/question/11292757

brainly.com/question/12978926

#LearnwithBrainly

3 0
3 years ago
Who was the first woman to compete and win a championship in the Olympics
natita [175]
Hélène de Pourtalès she was the first women
6 0
3 years ago
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