3. A skater moves across the ice a distance of 12 m before a constant frictional force of 15 N cause him to stop. His initial speed is 2.2 m/s . Calculate the skater's mass.

Answer:

false

Explanation:

Speed = distance / time

Speed = 120 km / 2 1/2 hours

Speed = 48 km per hour

Answer:

to be honest i dont know

Explanation:

^^

Answer:

y = y₀ / 4

Explanation:

In a double slit experiment the constructive interference lines are given by

          d sin θ = m λ

if we use trigonometry

          tan θ = y / L

as in these experiments the angles are very small

          tan θ = sin θ /cos θ = sin θ

we substitute

         sin θ = y / L

          d y / L = m λ

let's use a subscript "o" for the initial values  

          I = m λ₀ L /d₀

They ask us to decrease the wavelength by 2

           λ =  λ₀ / 2

the distance in the slit is increased by a factor of two

         d = 2 d₀

we substitute

          2d₀  y/L = m  λ₀/2

          y = m  λ₀ L/d₀    ¼

          y = y₀ / 4

Answer:

52.5 J

Explanation:

Applying,

Hook's law,

F = ke............... Equation 1

Where F = Force, k = spring constant, e = extension.

make k the subject of the equation

k = F/e............ Equation 2

From the question,

Given: F = 350 Newtons, e = 30 cm = 0.3 m

Substitute these values into equation 2

k = 350/0.3 N/m

Also,

W = 1/2(ke²).................. Equation 3

Where W = work done in stretching the spring.

Also given: e = (50-20) cm = 30 cm = 0.3 m, k = 350/0.3 N/m

Substitute these values into equation 3

W = 1/2(350/0.3)(0.3²)

W = 350×0.3/2

W = 52.5 J

Answer:

The distance traveled by the faster car when it is 15 mins ahead of the slower car is 165 miles.

Explanation:

Given;

speed of the faster car, v₁ = 60 mi/h

speed of the slower car, v₂ = 55 mi/h

Let the distance traveled by the faster car when it is 15 mins ahead of the slower car = x miles

[tex]\frac{x}{55} - \frac{x}{60} = \frac{15}{60}[/tex]

Note: divide 15 mins by 60 to convert to hours for consistency in the units.

[tex]\frac{x}{55} - \frac{x}{60} = \frac{15}{60}\\\\multiple \ through \ by \ 660\\\\12x - 11x = 165\\\\x = 165 \ miles[/tex]

Therefore, the distance traveled by the faster car when it is 15 mins ahead of the slower car is 165 miles.

Answer:

W = 3/2 n (T₁- T₂)

Explanation:

Let's use the first law of thermodynamics

           ΔE = Q + W

in this case the cylinder is insulated, so there is no heat transfer

           ΔE = W

internal energy can be related to the change in temperature

            ΔE = 3/2 n K ΔT

we substitute

           3/2 n (T₂-T₁) = W

as the work is on the gas it is negative

            W = 3/2 n (T₁- T₂)

As we know larger the area of contact lesser the pressure. So, in order to reduce the pressure heavy vehicles have broad tyres to increase the area of contact with the ground. Heavy vehicles have broad tyres because broad tyres have large area of contact and less pressure on the ground.

mark me brainliesttt pls :)))

Answer:

A

Explanation:

Answer:

Impulse = Average force x time of contact

Explanation:

Impulsive force is a force which is very large but applied on a body for a very small duration of time.

Impulse is given by the change in momentum of the body.

Impulse = Average force x small time interval

When padding is there, the time interval of contact is large and thus, the force exerted by the body is small.

So, when a person falls on the tile floor, there is no compression and thus, the time of contact is very small and thus the impulsive force is very large, due to  which the body may damage.

So, when a person falls on the carpeted floor, there is a compression and thus, the time of contact is comparatively large and thus the impulsive force is small, due to  which the body may safe.

Answer:

Explanation:

The angular momentum of that same disk-sphere remains unchanged the very same way before and after the impact of the collision when the clay sphere adheres to the disk.

 [tex]\mathbf{I_w}[/tex] = constant.

The overall value of such moment of inertia is now altered when the clay spherical sticks. Due to the inclusion of the clay sphere, the moment of inertia will essentially rise. As a result of this increase, the angular speed w decreases in value.

Recall that:

The Kinetic energy is given by:

[tex]\mathbf{K = \dfrac{1}{2} Iw^2} \\ \\\mathbf{K = \dfrac{1}{2} lw*w}[/tex]

where;

[tex]\mathbf{I_w}[/tex] is constant and w reduces;

As a result, just after the collision, the system's total kinetic energy decreases.

The total kinetic energy of the system decreases after the collision.

The angular momentum of any rotating body is defined as the product of the moment of inertia of the body and the angular velocity of the body.

Now from the question, we can see that the angular momentum of the body remains constant before and after the impact of the collision when the clay sphere adheres to the disk.

So angular momentum will be

[tex]Iw[/tex] = constant.

The overall value of such a moment of inertia is now changed when the clay spherical sticks. Due to the inclusion of the clay sphere, the moment of inertia will essentially rise. As a result of this increase, the angular speed w decreases in value.

The Kinetic energy is given by:

[tex]KE=\dfrac{1}{2} Iw^2[/tex]

[tex]KE= \dfrac{1}{2} Iw\times w[/tex]

Since the angular momentum [tex]Iw[/tex] is constant and w is reducing then ultimately the energy of the system is decreasing.

Thus the total kinetic energy of the system decreases after the collision.

To know more about Angular momentum follow

https://brainly.com/question/25677703

Answer: The egg will get sucked into the bottle. To get the egg out of the bottle, turn the bottle upside down and blow into it, so that the egg acts as a one-way valve. The increased air pressure in the bottle will cause the egg to pop back out.

Explanation:

Quickly place the egg over the mouth of the bottle. The egg will get sucked into the bottle. To get the egg out of the bottle, turn the bottle upside down and blow into it, so that the egg acts as a one-way valve. The increased air pressure in the bottle will cause the egg to pop back out.

Answer:

total time taken is 2.1389 seconds

Explanation:  

Given the data in the question and as illustrated in the diagram below;

They have measured the acceleration of the ball on the incline to be 2.5 m/s²

a = -2.5 m/s²    { negative because its acting downward }

from the diagram, Motion from B to C will be;

v² = u² + 2as

given that distance s = 1.1 m

we substitute

v² - u² = 2as

(0)² - u² =  2 × (-2.5 m/s ) × 1.1 m

-u² = -5.5

u = √5.5

so Initial speed; u = 2.345 m/s

to get the time, we use the equation of motion;

v = u + at

we substitute

0 = 2.345 m/s + ( -2.5 m/s² × t₁ )

2.5t₁ = 2.345

t₁ = 2.345 / 2.5

t₁ = 0.938 s

Now, from C to B

we determine t₂

s = vt₂ + [tex]\frac{1}{2}[/tex]at₂²

1.1 m = 0×t₂ + [tex]\frac{1}{2}[/tex] × 2.5 m/s² × t₂²

1.1 m = [tex]\frac{1}{2}[/tex] × 2.5 m/s² × t₂²

1.1 m = 1.25 m/s² × t₂²

t₂² = 1.1 m / 1.25 m/s²

t₂² = 0.88 s²

t₂ = √0.88 s²

t₂ = 0.938 s

Next, from B to A; t₃ will be;

s = ut₃ + [tex]\frac{1}{2}[/tex]at₃²

we substitute

0.7 m = (2.345 m/s)t₃ + [tex]\frac{1}{2}[/tex] × 2.5 m/s × t₃²

0.7 m = (2.345 m/s)t₃ + ( 1.25 m/s )t₃²

1.25t₃² + 2.345t₃ - 0.7 = 0

using; x = [ -b ± √( b² - 4ac ) ] / 2a

we substitute

x = = [ -2.345 ± √( (2.345)² - (4 × 1.25 × -0.7) ) ] / 2(1.25)

x = [ -2.345 ± √( 5.499 + 3.5 ) ] / 2.5

x =  [ -2.345 ± √( 8.999 ) ] / 2.5

x =  [ -2.345 ± 2.9998 ] / 2.5

x =  ( [ -2.345 - 2.9998 ] / 2.5 ) or ( [ -2.345 + 2.9998 ] / 2.5 )

x = -2.1379 or 0.2629

hence t₃ = 0.2629 s

∴ Total time = t₁ + t₂ + t₃

Total time = 0.938 s + 0.938 s + 0.2629 s

Total time = 2.1389 seconds

Therefore, total time taken is 2.1389 seconds

Answer:

B on edge2020-2021

Explanation:

Answer:

the correct answer is c

Explanation:

In this exercise we seek the momentum

          I = F t

this value is set because forces and time are given.

Now we can use the relationship between linear momentum and momentum

         I = p_f - p₀

         I = m v_f - m v₀

suppose that the two spheres depart with the same initial velocity

Let's analyze these results, the value of the impulse is the same, so the body of lower mass must acquire greater speed or momentum

consequently the lighter sphere acquires more final speed, but the change of momentum is the same in the two spheres

Consequently the correct answer is c

Answer:

the answer is the explaination

Explanation:

Present beach erosion prevention methods include sand dunes, vegetation, seawalls, sandbags, and sand fences. Based on the research conducted, it is evident that new ways to prevent erosion must be obtained. Each way that is currently used has extensive negative effects on beaches and their natural tendencies.

Answer:

They will construct strong sea walls with the intent to protect the coastline and infrastructure that could be affected by erosion.

Explanation:

wave velocity = frequency × wavelength

300 = frequency × 0.75

Frequency = 300÷0.75 = 400 HZ

Answer:

the energy possessed by a body by virtue of its position relative to others, stresses within itself, electric charge, and other factors.

hope this helps

have a good day :)

Explanation:

Answer:

Potential Energy is the stored energy in an object or system because of its position or configuration.

Explanation:

Example: Water at the top of a waterfall, before the precipice.

Answer:

a. True

Explanation:

Conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When the conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.

A conductor can be defined as any material or physical object that allows the conduction (transfer) of electric charge or thermal energy. Some examples of conductors are metal, steel, aluminum, copper, frying pan, pot, metallic spoon, etc.

During heat conduction, thermal energy is usually transferred from fast moving particles to slow moving particles during the collision of these particles.

Furthermore, any charge that is added to a conductor would quickly spread over the surface of the conducting object due to the fact that it allows the movement of subatomic particles.

Answer: True

Explanation: Aced Test

Answer:

1. 0.57 m/s

2. 25 Watts

Explanation:

1. Determination of the speed.

We'll begin by converting 1.5 hp to watt (W). This can be obtained as follow:

1 hp = 745.7 W

Therefore,

1.5 hp = 1.5 hp × 745.7 W / 1 hp

1.5 hp = 1118.55 W

Next, we shall determine the force. This can be obtained as follow:

Mass (m) = 200 Kg

Acceleration due to gravity (g) = 9.8 m/s²

Force (F) =?

F = m × g

F = 200 × 9.8

F = 1960 N

Finally, we shall determine the speed. This can be obtained as follow:

Power (P) = 1118.55 W

Force (F) = 1960 N

Speed (v) =?

P = F × v

1118.55 = 1960 × v

Divide both side by 1960

v = 1118.55 / 1960

v = 0.57 m/s

Thus, the speed is 0.57 m/s

2. Determination of the power.

We'll begin by calculating the velocity. This can be obtained as follow:

Displacement = 10 m up

Time = 20 s

Velocity =?

Velocity = Displacement / time

Velocity = 10 / 20

Velocity = 0.5 m/s

Finally, we shall determine the power. This can be obtained as follow:

Velocity (v) = 0.5 m/s

Force (F) = 50 N

Power (P) =?

P = F × v

P = 50 × 0.5

P = 25 Watts

Therefore, the power required to lift the bucket is 25 Watts

Answer:

Equations of motion relate the displacement of an object with its velocity, acceleration and time. s=vt where s is the displacement, v the (constant) speed and t the time over which the motion occurred. ...

Displacement with negative acceleration: s, equals, v, t, minus, one half, a, t, square...

Displacement with positive acceleration: s, equals, u, t, plus, one half, a, t, squared,s...

Velocity squared: v, squared, equals, u, squared, plus, 2, a, s,v2=u2+2as

Velocity: v, equals, u, plus, a, t,v=u+at

Answer:

The spring constant is 173.12 N/m.

Explanation:

mass, m = 32 kg

Period, T = 2.7 s

let the spring constant is K.

Use the formula of period,

[tex]T = 2\pi\times \sqrt \frac{m}{K}\\\\2.7 =2\times 3.14\sqrt\frac{32}{K}\\\\K = 173.12 N/m[/tex]

Answer:

the distance of image from the vertex is 45 cm and the image formed is in the glass.

Explanation:

distance of object, u = - infinity

radius of curvature, R = - 15 cm

refractive index, n = 1.5

Let the distance of image is v.

Use the formula

[tex]-\frac{n1}{u}+\frac{n2}{v}=\frac{n2- n1}{R}\\\\-\frac{1}{\infty }+\frac{1.5}{v}=\frac{1.5-1}{-15}\\\\v=45 cm[/tex]

The image is in the glass.  

Answer:

the correct answer is B

Explanation:

The quantum numbers are the constants obtained when solving the Schrodinger equation, the first quantum number or principal quantum number (n), can take values ​​from zero to infinity.

This quantum number is placed as a coefficient in the quantum distribution.

In this case for phosphorus, the number is n = 3

the correct answer is B

Answer:

s = 11250 m = 11.25 km

Explanation:

The distance covered by the sound wave while traveling from submarine to ocean floor and then back to submarine can be given as follows:

[tex]s = vt[/tex]

but, the distance between the floor and the submarine will be half of this value:

[tex]s = \frac{1}{2}vt[/tex]

where,

s = distance between submarine and ocean floor = ?

v = velocity of sound = 1500 m/s

t = time taken for the round trip = 15 s

Therefore,

[tex]s = \frac{1}{2}(1500\ m/s)(15\ s)[/tex]

s = 11250 m = 11.25 km

Answer:

This is because the age of the universe is determined by the pace of expansion in the past, and each model forecasts a different pace.

Explanation:

The age of the universe is determined by the pace of expansion in the past, and each model forecasts a different pace.

This is due to the fact that the expansion rate in the coasting model is constant and never changes. Because the cosmos is growing faster now than during the old days, recollapsing and critical models give shorter ages. According to the accelerating model, the universe is growing at a slower rate currently than in the past, implying an older age.

Complete question:

while hunting in a cave a bat emits sounds wave of frequency 39 kilo hartz were moving towards a wall with a constant velocity of 8.32 meters per second take the speed of sound as 340 meters per second. calculate the frequency​ reflected off the wall to the bat?

Answer:

The frequency reflected by the stationary wall to the bat is 41 kHz

Explanation:

Given;

frequency emitted by the bat, f = 39 kHz

velocity of the bat, [tex]v_b[/tex] = 8.32 m/s

speed of sound in air, v = 340 m/s

Apply the doppler-effect principle to solve this problem.

The apparent frequency of sound striking the wall is calculated as;

[tex]f' = f(\frac{v}{v- v_b} )\\\\f' = 39,000(\frac{340}{340 -8.32} )\\\\f' = 39978.29 \ Hz[/tex]

The frequency reflected by the stationary wall to the bat is calculated as;

[tex]f_s = f'(\frac{v + v_b}{v} )\\\\f_s = 39978.29(\frac{340 + 8.32}{340} )\\\\f_s = 40,956.56 \ Hz[/tex]

[tex]f_s\approx 41 \ kHz[/tex]

Answer: [tex]4.65\ m/s[/tex]

Explanation:

Given

Distance putty has to travel is 3.5 m

The initial speed of putty is 9.50 m/s

Using equation of motion to determine the velocity of putty just before it hits ceiling

[tex]v^2-u^2=2as[/tex]

[tex]\Rightarrow v^2-(9.5)^2=2(-9.8)(3.5)\\\\\Rightarrow v^2=9.5^2-68.6\\\Rightarrow v=\sqrt{90.25-68.6}\\\Rightarrow v=4.65\ m/s[/tex]

So, the velocity of putty just before hitting is [tex]4.65\ m/s[/tex]

Answer:

the answer should be D

Explanation:

Because if you want to earn your goals you must complete small goals to earn big goals