To a stationary observer, a bus moves south with a speed of 12 m/s. A man
inside walks toward the back of the bus with a speed of 0.5 m/s relative to
the bus. What is the velocity of the man according to a stationary observer?
A. 11 m/s south
B. 12.5 m/s south
C. 11.5 m/s south
D. 0.5 m/s south

Answer:

0.252 m/s

Explanation:

Applying the law of conservation of momentum,

Total momentum before collision = Total momentum after collision

Note: From the question, The collision between the car and the train is an inelastic collision and as such, both move with a common velocity after collision.

mu+m'u' = V(m+m')................... Equation 1

Where m = mass of the train, u' = initial velocity of the train, m' = mass of the car, u' = initial velocity of the car, V = common velocity after collision.

make V the subject of the equation

V = (mu+m'u')/(m+m')............... Equation 2

Given: m = 270000 kg, u = 0.325 m/s, m' = 52500 kg, u' = -0.12 m/s

Substitute these values into equation 2

V = [(270000×0.325)+{52500(-0.12)}]/(270000+52500)

V = 81450/322500

V = 0.252 m/s

Answer:

462000J

Explanation:

Quantity of heat= mass x specific heat capacity of iron x change in temp

specific heat capacity of iron is 462J/Kg/K

change in temp = 250-50= 200°C

200°C is equivalent to 200K since 1°C is 1K

Q= mct

= 5x462x200

= 462000J

Answer:

You should still workout 90 min.

The proper time is measured by a single clock in a single place.

The proper time on earth is 90 min.

The clock on the rocket is also in a single place in the frame of the rocket so you still need to workout for 90 min.

Answer:

[tex]118\; \rm Hz[/tex].

Explanation:

The frequency [tex]f[/tex] of a wave is equal to the number of wave cycles that go through a point on its path in unit time (where "unit time" is typically equal to one second.)

The wave in this question travels at a speed of [tex]v= 295\; \rm m\cdot s^{-1}[/tex]. In other words, the wave would have traveled [tex]295\; \rm m[/tex] in each second. Consider a point on the path of this wave. If a peak was initially at that point, in one second that peak would be

How many wave cycles can fit into that [tex]295\; \rm m[/tex]? The wavelength of this wave[tex]\lambda = 2.50\; \rm m[/tex] gives the length of one wave cycle. Therefore:

[tex]\displaystyle \frac{295\;\rm m}{2.50\; \rm m} = 118[/tex].

That is: there are [tex]118[/tex] wave cycles in [tex]295\; \rm m[/tex] of this wave.

On the other hand, Because that [tex]295\; \rm m[/tex] of this wave goes through that point in each second, that [tex]118[/tex] wave cycles will go through that point in the same amount of time. Hence, the frequency of this wave would be

Because one wave cycle per second is equivalent to one Hertz, the frequency of this wave can be written as:

[tex]f = 118\; \rm s^{-1} = 118\; \rm Hz[/tex].

The calculations above can be expressed with the formula:

[tex]\displaystyle f = \frac{v}{\lambda}[/tex],

where

Answer:

118

Explanation:

Answer:

Los datos que tenemos:

Rapidez: 69km/h

Tiempo que tarda en frenar = 4s.

Distancia inicial entre la tracto-mula y la vaca = 25m

Ok, la ecuación de desaceleración es:

D = (sf - si)/t

sf = velocidad final = 0m/s

si = velocidad inicial = 69km/h

t = tiempo = 4s

D = -69km/h/4s

ok, 1h = 3600s

D = (-69km/s)*1/(4*3600s)  = -0.0048 km/s^2

Entonces la ecuación de aceleración es:

a(t) =  -0.0048 km/s^2

Para la velocidad, integramos sobre el tiempo

v(t) = (-0.0048 km/s^2)*t + v0

donde v0 es la velocidad inicial, en este caso v0 = 69km/3600s = 0.0191km/s  

v(t) =  (-0.0048 km/s^2)*t + 0.0191km/s

Para la posición volvemos a integrar sobre el tiempo, esta vez suponemos la posición inicial igual a cero.

p(t) = (1/2)*(-0.0048 km/s^2)*t^2 + 0.0191m/s*t

Ahora, si p(t=4s) < 25m, esto implica que la tracto-mula no impacto con la vaca.

p(4s) = (1/2)*(-0.0048 km/s^2)*(4s)^2 + 0.0191km/s*4s = 0.038km

y 1km = 1000m

0.038km = 0.038*1000m = 38m

Entonces si, atropello a la vaca.

When a snowball turns into a puddle of water, we know that (the snow ball gains energy and changes from a solid to liquid).

This is correct due to the fact that particles of the snowball are gaining speed and so it is heating up, when the solid's temperature reaches the melting point, it will become a liquid.

Therefore, D is the correct answer.

Answer: 14000 N

Explanation: i just did it on khan academy

Answer:

Explanation:

Solution,

When a certain object comes in motion from rest, in the case, initial velocity = 0 m/s

Initial velocity ( u ) = 0 m/s

Final velocity ( v ) = 72 km/h ( Given)

We have to convert 72 km /h in m/s

[tex]72 \: km \: per \: hour[/tex]

[tex] = 72 \times \frac{1000}{60 \times 60} [/tex]

[tex] = 20 [/tex] m/s

Final velocity ( v ) = 20 m/s

Time taken ( t ) = 2 seconds

Acceleration (a) = ?

Now,

we have,

[tex]a = \frac{v - u}{t} [/tex]

[tex]a = \frac{20 - 0}{2} [/tex]

[tex]a = \frac{20}{2} [/tex]

[tex]a = 10 [/tex] m/s ^2

Hope this helps...

Good luck on your assignment..

Answer:

Explanation:

just use the gravational force equation which is G x m of earth x m of object divided by r squared (which is radius of earth)

Answer:

acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities. The orientation of an object's acceleration is given by the orientation of the net force acting on that object.

Explanation:

Calculating acceleration involves dividing velocity by time — or in terms of SI units, dividing the meter per second [m/s] by the second [s]. Dividing distance by time twice is the same as dividing distance by the square of time. Thus the SI unit of acceleration is the meter per second squared .

Answer:

a. 2 Hz b. 0.5 cycles c . 0 V

Explanation:

a. What is period of armature?

Since it takes the armature 30 seconds to complete 60 cycles, and frequency f = number of cycles/ time = 60 cycles/ 30 s = 2 cycles/ s = 2 Hz

b. How many cycles are completed in T/2 sec?

The period, T = 1/f = 1/2 Hz = 0.5 s.

So, it takes 0.5 s to complete 1 cycles. At t = T/2 = 0.5/2 = 0.25 s,

Since it takes 0.5 s to complete 1 cycle, then the number of cycles it completes in 0.25 s is 0.25/0.5 = 0.5 cycles.

c. What is the maximum emf produced when the armature completes 180° rotation?

Since the emf E = E₀sinθ and when θ = 180°, sinθ = sin180° = 0

E = E₀ × 0 = 0

E = 0

So, at 180° rotation, the maximum emf produced is 0 V.

Answer:

d) harvesting and threshing both.

Explanation:

Hope it helps you...

Answer:

a. q = qm/√2 b. qm/√(2LC)

Explanation:

a. Charge on the capacitor

Let U₁ = energy in inductor and U₂ = energy in capacitor and U = total energy in circuit.

So, U₁ + U₂ = U.

Since the energy is shared equally between the capacitor and inductor, U₁= U₂,so

2U₂ = U

and U₂ = U/2

Now U₂ = q²/2C where q is the charge on the capacitor with capacitance C and

U = (qm)²/2C where qm is the maximum charge on the capacitor.

Since U₂ = U/2,

Substituting the values for U₂ and U, we have

q²/2C = [(qm)²/2C]/2

q² = (qm)²/2

taking square-root of both sides, we have

q = qm/√2

b. The current in the inductor

Since the energy in the capacitor equals the energy in the inductor,

1/2LI² = 1/2q²/C where L is the inductance of the inductor and I the current through it.

I² = q²/LC

taking square-root of both sides, we have

I = q/√LC

substituting the value of q from above, we have

I = qm/√2 ÷ √LC

I = qm/√(2LC)

Answer:

The correct answer is "0.246".

Explanation:

Given that the amplitude is decreased by a factor of 9, then

[tex]A \rightarrow (A-\frac{A}{9} )[/tex]

[tex]A \rightarrow \frac{8A}{9}[/tex]

As we know,

Energy will be:

⇒  [tex]E_{1}=\frac{1}{2}KA^2[/tex]

and,

⇒  [tex]E_{2}=\frac{1}{2}K(\frac{8A}{9} )^2[/tex]

          [tex]=\frac{64KA^2}{162}[/tex]

⇒  [tex]\Delta E=E_1-E_2[/tex]

On putting the estimated values, we get

           [tex]=\frac{1}{2}KA^2-\frac{64KA^2}{162}[/tex]

⇒  [tex]\frac{\Delta E}{E}=\frac{\frac{20}{162}KA^2}{\frac{1}{2}KA^2}[/tex]

          [tex]=\frac{40}{162}[/tex]

          [tex]=0.246[/tex]

Answer:

C 80 m

Explanation:

Given:

v₀ = 30 m/s

a = -10 m/s²

t = 8 s

Find: Δy

Δy = v₀ t + ½ at²

Δy = (30 m/s) (8 s) + ½ (-10 m/s²) (8 s)²

Δy = -80 m

The ball lands 80 m below where it started.  So the height of the cliff is 80 m.

Answer:

Explanation:

In this problem we are required to find the potential energy possessed by the television

Given data

mass of television m = 15 kg

height  added above the ground, h= 1-0.3 = 0.7 m

acceleration due to gravity g = 9.81 m/s^2

apply the formula for potential energy we have

P.E= m*g*h

P.E = 15*9.81*0.7 = 103 Joules

Answer:

1.125x10^-10 electrons

Explanation:

Pls see attached file

Answer:

625 cm²

Explanation:

The pressure is the same on both pistons.

F/A = F/A

200 N / 25 cm² = 5000 N / A

A = 625 cm²

Answer:

Translatory Motion:

The motion of a body along a line is called Translatory Motion. The line may be straight or curved. There are three types:

1) Linear Motion:

Straight line motion of a body is called Linear Motion.

E.g. Movement of a car on a straight road.

2) Circular Motion:

Motion of a body along a circle is called circular motion.

E.g. Movement of a toy train along its circular track.

3) Random Motion:

The irregular motion of a body is called random motion.

E.g. Movement of a bee.

.......Hope it helps :)........

Answer:

v = 46.67 km/h

Explanation:

We will use the following formula throughout this numerical:

s = vt

where,

s = distance covered

v = speed

t =  time taken

FOR FIRST 30 km:

s = 30 km

v = 30 km/h

t = t₃₀ = ?

Therefore,

30 km = (30 km/h)(t₃₀)

t₃₀ = (30 km)/(30 km/h)

t₃₀ = 1 h

FOR TOTAL 100 km:

s = 100 km

v = 40 km/h (Average Speed)

t = total time = ?

Therefore,

100 km = (40 km/h)(t)

t = (100 km)/(40 km/h)

t = 2.5 h

FOR LAST 70 km:

s = 70 km

t₇₀ = t - t₃₀ = 2.5 h - 1 h = 1.5 h

v = v₇₀ = ?

Therefore,

70 km = v(1.5 h)

v = 70 km/1.5 h

v = 46.67 km/h

Answer:

   f = 6.37 Hz,       T = 0.157 s

Explanation:

The expression you have is

       y = 5 sin (3x - 40t)

this is the equation of a traveling wave, the general form of the expression is

      y = A sin (kx - wt)

where A is the amplitude of the motion, k the wave vector and w the angular velocity

Angle velocity and frequency are related

         w = 2π f

         f = w / 2π

from the equation w = 40 rad / s

        f = 40 / 2π

        f = 6.37 Hz

frequency and period are related

       f = 1 / T

       T = 1 / f

       T = 1 / 6.37

       T = 0.157 s

Answer:

d. She will be slightly lower than you but moving upward toward you.

Explanation:

Since your swing is slightly shorter than your friend's swing, then you will have more angular speed than your friend. Angular speed increases with a decrease in radius. The closer the body is to the center, the faster the body swings. By the time you would have completed one complete swing back and forth, your friend will just be moving towards you, and she will be slightly lower than you but moving upwards towards you. This principle is the same reason gymnasts pull their limbs closer to their body when they need to swing faster.

Answer:

greatest displacement = 44.1m

initial velocity= 29.4m/s

Explanation:

Greatest displacement

s=1/2at^2

= (9.8/2 ×9)m

= 44.1m

initial velocity

s=ut-1/2at^2

44.1= 3u -(1/2×9.8×9)

44.1=3u-44.1

3u=88.2

u=29.4m/s

Answer:

cluttered

Explanation:

The correct word to describe the garage would be cluttered.

A place is said to be cluttered when it is filled with an untidy collection of material things. In this case, the garage is filled with materials such as bike wrenches, tires, frames, etc.

Inviting can also mean tempting, attractive, etc, and has no relevance to the condition of the garage as described in the excerpt.

Dangerous can also mean harmful, and not the right word to describe the garage.

Sparse can also mean scanty, scattered, and would be the opposite of the condition of the garage.

Correct answer: cluttered

Answer:

c.  cluttered

Explanation:

Answer:

The equivalent or total resistance of the circuit is 6

Explanation:

6 &6 are in series

6+6=r

r= 12

1/Rtotal= 1/12+1/2

1/Rt=2/12=1/6

Rt=6

Explanation:

momentum = mass x velocity

initial momentum = 100 x 15 = 1500kgm/s

after momentum = 100 x 20 = 2000kgm/s

a =(v-u)/t

a = (20-15)/10

a = 5/10

a = 0.5m/s²

f = ma

f = 100 x 0.5

f = 50N

Answer:

3 m/s²

Explanation:

Sum of forces in the x direction:

∑F = ma

68 N − 23 N = (15 kg) a

a = 3 m/s²

Answer:

On heating gases expands than solid and liquid because the molecules gets seperated and the volume increases that causes to expand.

Explanation:

Hope it is helpful

please mark me as brainliest

please

Answer:

b. Red light is transmitted through and reflected by the glass

Explanation:

Give me brainliest plz!

All of the wavelengths of the red light are absorbed when it passes through a translucent red glass window, but the red light is transmitted and reflected.

Therefore, the correct answer is option b) Red light is transmitted through and reflected by the glass.

To learn more about light refer to:

https://brainly.com/question/12002703

#SPJ2

Answer:

*  most of the emission would be in the infrared part, the visible radiation would be very small.

*total intensity of the semition decreases that the intensity depends on the fourth power of the temperature

Explanation:

The radiation emitted by the Sun is approximately the radiation of a black body, if the Sun were to cool, the maximum emission wavelength changes

          λ T = 2,898 10⁻³

          λ = 2,898 10⁻³ / T

if the temperature decreases the maximum wavelength the greater values ​​are moved, that is to say towards the infrared. Therefore the emission curve also moves, in this case most of the emission would be in the infrared part, the visible radiation would be very small.

Furthermore, the total intensity of the semition decreases that the intensity depends on the fourth power of the temperature according to Stefan's law

           P = σ A eT⁴