Fig. 2.1 shows a train
Fig. 2.1
The total mass of the train and its passengers is 750000kg. The train is travelling at a speed of 84m/s.
The driver applies the brakes and the train takes 80s to slow down to a speed of 42m/s.
(a) Calculate the impulse applied to the train as it slows down,
impulse =
[3]
(b) Calculate the average resultant force applied to the train as it slows down,
force =
(2)

Answer:

c

Explanation:

speed=distance÷time

40÷10=4

Polar substances are likely to dissolve in polar solvents.

Your answer is B.

Answer:

Approximately [tex]5.5\; \rm N[/tex], assuming that the volume of these two charged objects is negligible.

Explanation:

Assume that the dimensions of these two charged objects is much smaller than the distance between them. Hence, Coulomb's Law would give a good estimate of the electrostatic force between these two objects regardless of their exact shapes.

Let [tex]q_1[/tex] and [tex]q_2[/tex] denote the magnitude of two point charges (where the volume of both charged object is negligible.) In this question, [tex]q_1 = 20 \times 10^{-6}\; \rm C[/tex]  and [tex]q_2 = 15 \times 10^{-6}\; \rm C[/tex].

Let [tex]r[/tex] denote the distance between these two point charges. In this question, [tex]r = 0.7\; \rm m[/tex].

Let [tex]k[/tex] denote the Coulomb constant. In standard units, [tex]k \approx 8.98755\times 10^{9}\; \rm kg \cdot m^{3}\cdot s^{-2}\cdot C^{-2}[/tex].

By Coulomb's Law, the magnitude of electrostatic force (electric force) between these two point charges would be:

[tex]\begin{aligned}F &= \frac{k \cdot q_1 \cdot q_2}{r^{2}}\end{aligned}[/tex].

Substitute in the values and evaluate:

[tex]\begin{aligned}F &= \frac{k \cdot q_1 \cdot q_2}{r^{2}}\\ &\approx 8.98755 \times 10^{9}\; \rm kg \cdot m^{3}\cdot s^{-2}\cdot C^{-2} \\ &\quad \times 20\times 10^{-6}\; \rm C\\ &\quad \times 15\times 10^{-6}\; \rm C \\ &\quad \times \frac{1}{{(0.7\; \rm m)}^{2}}\\ &\approx 5.5\; \rm N \end{aligned}[/tex].

Answer:

The new force is 2/3 of the original force

Explanation:

Coulomb's Law

The electrical force between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between the two objects.

Written as a formula:

[tex]\displaystyle F=k\frac{q_1q_2}{d^2}[/tex]

Where:

[tex]k=9\cdot 10^9\ N.m^2/c^2[/tex]

q1, q2 = the objects' charge

d= The distance between the objects

Suppose the first charge is doubled (2q1) and the second charge is one-third of the original charge (q2/3). Now the force is:

[tex]\displaystyle F'=k\frac{2q_1*q_2/3}{d^2}[/tex]

Factoring out 2/3:

[tex]\displaystyle F'=\frac{2}{3}k\frac{q_1*q_2}{d^2}[/tex]

Substituting the original force:

[tex]F'=\frac{2}{3}F[/tex]

The new force is 2/3 of the original force

The point B represent the crest of the wave. The crest is the peak of the wave. While the trough is the lowest.

The distance between two successive troughs or crests is known as the wavelength.

The wavelength is also defined as the distance between two locations in a wave that have the same oscillation phase.

The point B represent the crest of the wave. The crest is the peak of the wave. While the trough is the lowest.

Hence, option B is correct.

To learn more about the wavelength, refer to the link;

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Answer:

The answer is A good luck :P

Answer:

A

Explanation:

The light Bounces off because it is reflecting off glass or anything else

Answer:

Ver la explicación a continuación.

Explanation:

En física estas siglas significan movimiento rectilíneo uniforme, es decir es el tipo de movimiento donde la velocidad es constante. La velocidad no cambia con el tiempo.

Este tipo de movimiento se puede describir con la siguiente ecuación.

[tex]x=x_{0}+v*t[/tex]

Donde:

x = posición final [m]

xo = posición inicial [m]

v = velocidad [m/s]

t = tiempo [s]

Explanation:

Hope it helps..........

Answer:

the answer is 4

Explanation:

the picture matches eachother that's why I picked 4

Answer:

devils tower

Explanation:

on the topographic map the circular lines stop at at certain point because the moutain doesnt get any pointyer if you know what that means

in other words if the map continued with the circular lines all the way to the centerit would have been that snowny mountain

Answer:

B

Explanation:

Speed is distance divided by time.

Answer:

The torque necessary to bring the wheel to rest in 40 seconds is 10.4 N·m

Explanation:

The question is with regards to rotational motion

The rotary motion parameters are;

The mass of the wheel = 50 kg

The radius of the wheel = 0.4 m

The rate of rotation of the wheel = 480 rpm

The time in which the wheel is to be brought to rest = 40 s

The rotational rate of the wheel in rotation per second is given as follows;

480 r.p.m = 480 r.p.m × 1 minute/(60 seconds) = 8 revolution/second

1 revolution = 2·π radians

Therefore, we have the angular velocity, ω, given as follows;

ω = 2·π × 8 revolutions/second ≈ 50.3 rad/s

The angular acceleration, α, is given as follows;

[tex]\alpha = \dfrac{\Delta \omega}{\Delta t} = \dfrac{\omega _2 - \omega_1}{t_2 - t_1}[/tex]

Whereby the wheel is brought to rest from its initially constant rotational motion in 40 seconds, we have;

ω₁ ≈ 50.3 rad/s, ω₂ = 0 rad/s, and t₂ - t₁ = 40 seconds

Plugging in the values for the variables of the equation for the angular acceleration, "α", we get;

[tex]\alpha = \dfrac{0 - 50.3 \ rad/s}{40 \ s} \approx 1.3 \ rad/s^2[/tex]

The torque on the wheel, τ, is given as follows;

τ = m·r²·α

Where;

m = The mass of the object = 50 kg

r = The radius of the wheel = 0.4 m

α = The acceleration of the wheel ≈ 1.3 rad/s²

Therefore;

τ = 50 kg × (0.4 m)² × 1.3 rad/s² ≈ 10.4 N·m

The torque necessary to bring the wheel to rest in 40 seconds = τ ≈ 10.4 N·m.

Answer:

-10.048 N m

Explanation:

element z are isotopes because number of netron are different and number of protons are same

Answer:

8 J and 2 J

Explanation:

Given that,

Mass of the rubber ball, m = 1 kg

Initial speed of the rubber ball, u = 4 m/s (in east)

Final speed of the rubber ball, v = -2 m/s (in west)

We need to find the kinetic energy of the ball before it hits the wall, the kinetic energy of the ball after it bounces off the wall.

Initial kinetic energy,

[tex]K_i=\dfrac{1}{2}mv^2\\\\K_i=\dfrac{1}{2}\times 1\times (4)^2\\\\K_i=8\ J[/tex]

Final kinetic energy,

[tex]K_f=\dfrac{1}{2}mv^2\\\\K_f=\dfrac{1}{2}\times 1\times (2)^2\\\\K_f=2\ J[/tex]

So, the initial kinetic energy is 8 J and the final kinetic energy is 2 J.

The kinetic energy of the ball after it bounces off the wall is 2.0 Joules.

The kinetic energy of an object is the energy that is in motion or performing work. It can be expressed by using the formula:

[tex]\mathbf{K.E = \dfrac{1}{2}mv^2}[/tex]

The Kinetic energy of the ball after the collision and when it bounces off the wall is computed as:

[tex]\mathbf{K.E = \dfrac{1}{2} \times 1 \times 2.0^2}[/tex]

K.E = 2.0 Joules

Learn more about kinetic energy here:

https://brainly.com/question/8101588

Answer:

Total momentum = 50kgm/s

Explanation:

Given the following data;

Mass, M1 = 5kg

Mass, M2 = 7kg

Velocity, V1 = 10m/s

Velocity, V2 = 0m/s (since it's at rest).

To find the total momentum;

Momentum can be defined as the multiplication (product) of the mass possessed by an object and its velocity. Momentum is considered to be a vector quantity because it has both magnitude and direction.

Mathematically, momentum is given by the formula;

[tex] Momentum = Mass * Velocity [/tex]

The law of conservation of momentum states that the total linear momentum of any closed system would always remain constant with respect to time.

Total momentum = M1V1 + M2V2

Substituting into the equation, we have;

Total momentum = 5*10 + 7*0

Total momentum = 50 + 0

Total momentum = 50 kgm/s

Therefore, the total momentum of the bowling ball and the putty after they collide is 50 kgm/s.

Answer:

90m/s

Explanation:

Given parameters:

Acceleration  = 10m/s²

Time of fall  = 9s

Unknown:

Final velocity  = ?

Solution:

We can assume that the cart falls from rest.

   Initial velocity  = 0m/s

Using

        v  = u + gt

v is the final velocity

u is the initial velocity

g is the acceleration due to gravity

t is the time

       v  = 0 + 10 x 9  = 90m/s

Answer:

90m/s

Explanation:

Answer:

False

Explanation:

Electromagnetic waves are transverse waves. That means that the electric and magnetic fields oscillate in a plane that is perpendicular to the direction of wave propagation.

Answer:

false electromagnetic waves are not classified as longitudinal waves

Answer: Jack.

Explanation:

Momentum is defined as the quantity of motion.

For an object that has a mass M, and a velocity V, the momentum is written as:

P = M*V

For this problem, we know that Jack and Jill had the same speed (so they had the same velocity), let's say that this velocity is v.

Then the momentum of Jack will be:

P = 90kg*v

And the momentum of Jill will be:

P = 50kg*v

We can see that Jack will have a larger momentum, and this is because he has a larger mass than Jill, but the same velocity as her.

Answer:

I think the first two one is 70 the second on is 14

I hope this helps if I’m wrong I’m sorry

Explanation:

Answer:

25 km/h

Explanation:

speed=distance÷time

125÷5=speed

125÷5=25 (then add units)

Answer:

D is the correct answer

Explanation:

Ek=m*g*h=50*9.8*5=2450

The kinetic energy right before she hits the water is 2450J. So, the correct option is D.

Kinetic energy is defined as the energy that is due to the motion of an object. If we want to accelerate an object, we must apply a force, by applying a force we need to do work. After the work is done, energy has been transferred to the object, and the object will continue to move with a new constant speed.

A 50Kg girl jumps off a 5-meter-high diving board.

We need to find the kinetic energy of the girl before she enters the water which means that the kinetic energy becomes equal to the potential energy such that,

P.E.=K.E. = mgh

where, m=mass of the object

g= acceleration due to gravity [tex](9.8m/s^2)[/tex]

h= height

So, K.E= 50* 9.8*5 = 2450 J

Thus, the kinetic energy right before she hits the water is 2450J. So, the correct option is D.

Learn more about Kinetic energy, here:

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Answer:

A atmospheric composition

Answer:

C, T=D/S

Explanation:

Answer:

31.5m/s

Explanation:

Given the following

acceleration a = 4.5m/s²

Time t= 7secs

Required

Final speed v = ?

Using the equation of motion

v = u+at

v = 0+4.5(7)

v = 31.5m/s

Hence the speed of the dog is 31.5m/s

Answer:

[tex]1.5\cdot 10^{-5}\:\mathrm{N}[/tex]

Explanation:

Newton's Law of Gravitation is given as:

[tex]F=G\frac{m_1m_2}{r^2}[/tex], where [tex]G[/tex] is gravitational constant [tex]6.67\cdot 10^{-11}[/tex] and [tex]r[/tex] is the distance between their centers of mass.

Therefore, the gravitational force between them is:

[tex]F=6.67\cdot 10^{-11}\frac{55\cdot40}{0.1^2}= \fbox{$1.5\cdot 10^{-5}\:\mathrm{N}$}[/tex] (two significant figures).

Answer: i think its c

Explanation:

Answer:

a

Explanation:

Answer:

20 Hz, 20000 Hz

0.0166 m, 16.6 m

Explanation:

The minimum frequency that a human ear can hear is 20 Hz

The maximum frequency that a human ear can hear is 20000 Hz.

v = Velocity of sound = 332 m/s

Wavelength is given by

[tex]\lambda=\dfrac{v}{f}\\\Rightarrow \lambda=\dfrac{332}{20}\\\Rightarrow \lambda=16.6\ \text{m}[/tex]

The longest wavelength that can be heard by the human ear is 16.6 m

[tex]\lambda=\dfrac{332}{20000}\\\Rightarrow \lambda=0.0166\ \text{m}[/tex]

The shortest wavelength that can be heard by the human ear is 0.0166 m.

Answer:

Explanation:

A) Large: As she opens her parachute, she begins to displace a large volume of air. This leads to a Large air resistance

B) increase, weight: As she falls, the air resistance force increases. Now there is a force acting in opposite directions to her weight.

C)Weight, Decelerate: The skydiver has only the downward force of her weight pulling down on her, so she starts to decelerate

D) Weight, Upward, Resultant:

Her weight is now equal to the upward force from the ground. Her resultant  force is then zero

E) Increases, same, constant,  resultant, terminal:

As she accelerates faster, the air resistance force increases. It is now the same as her weight. She now moves at a constant speed because the resultant force acting on her is zero. She is now at her terminal velocity.

F) Increases, same, constant, terminal:

As she decelerates, the air resistance force on her parachute increases until it is the same as her weight. She is now moving with a constant speed until she hits the ground - a new slower terminal velocity

Answer:

[tex]4\:\mathrm{m}[/tex]

Explanation:

The formula for work is given as [tex]W=F\Delta x[/tex] where [tex]F[/tex] is force applied and [tex]\Delta x[/tex] is displacement.

Rearranging this equation, we have:

[tex]\Delta x=\frac{W}{F}[/tex].

Plugging in given values, we get:

[tex]\Delta x=\frac{W}{F}=\frac{320}{80}=\fbox{$4\:\mathrm{m}$}[/tex].

Answer:

The answer is 4m

Explanation:

hope this helps!

Answer:

elements

not really an explanation