A 80-kg person stands at rest on a scale while pulling vertically downwards on a rope that is above them. Use g = 9.80 m/s2.

With what magnitude force must the tension in the rope be pulling on the person so that the scale reads 25% of the persons weight?

Answer:

199.28 N

Explanation:

It is given that,

A spring stretches by 21.0 cm when a 135 N object is attached.

We need to find the weight of a fish that would stretch the spring by 31 cm.

We know that, the force in a spring is given by as per Hooke's law as follows :

F = kx

Where k is spring constant

[tex]\dfrac{F_1}{F_2}=\dfrac{x_1}{x_2}\\\\\dfrac{135}{F_2}=\dfrac{21}{31}\\\\F_2=\dfrac{135\times 31}{21}\\\\F_2=199.28\ N[/tex]

So, the required weight of a fish is 199.28 N.

Answer:

A

Explanation:

if you divide the 8100 km by the 27 hours you will get 300 km per hour

Answer:

The average force exerted on a person assuming that the water splashes sideways in all directions is 150 newtons.

Explanation:

From Fluid Mechanics and Newton's Laws we know that water stream is an example of a variable mass system at constant speed and the magnitude of the net force done by the water splash ([tex]F[/tex]), measured in newtons, is given by the following expression:

[tex]F = \rho\cdot \frac{dV}{dt}\cdot v[/tex] (Eq. 1)

Where:

[tex]\rho[/tex] - Density of water, measured in kilograms per cubic meter.

[tex]\frac{dV}{dt}[/tex] - Volume flow rate, measured in cubic meters per second.

[tex]v[/tex] - Flow velocity, measured in meters per second.

If we know that [tex]\rho = 1000\,\frac{kg}{m^{3}}[/tex], [tex]\frac{dV}{dt} = 0.03\,\frac{m^{3}}{s}[/tex] and [tex]v = 5\,\frac{m}{s}[/tex], the average force exerted on a person is:

[tex]F = \left(1000\,\frac{kg}{m^{3}} \right)\cdot \left(0.03\,\frac{m^{3}}{s} \right)\cdot \left(5\,\frac{m}{s} \right)[/tex]

[tex]F = 150\,N[/tex]

The average force exerted on a person assuming that the water splashes sideways in all directions is 150 newtons.

Answer:

We are given both the Force applied by the truck and the acceleration of the  truck:

Force applied (F) = 14,000 N

Acceleration (a)=  5 m/s²

Solving for the mass of the truck:

From Newton's second law of motion,

F = ma    (where F is the force applied , m is the mass of the object and a is the acceleration of the object)

replacing the variables:

14000 = (m)* 5

m = 14000/5

m = 2800

Therefore, the mass of the truck is 2800 kg

Answer:

m = 2800 N

Explanation:

14000 = (m)* 5

m = 14000/5

F= 14,000 N

a= 5 m/s^2

Answer:

The new angle of deflection north pole becomes smaller.

Explanation: The angle of deflection is the angle formed when an object changes course from its original course of direction or target.

The angle of deflection of a particular particle is directly proportional to its charge to mass ratio as it passed through an electric field.

As the wire is continously being lowered farther from the compass,the angle of deflection of the north pole ontinues to become smaller when compared to its initial deflection.

Answer:

Explanation:

cross sectional area = width x thickness

A = 30 x 10⁻² x 15 x 10⁻⁶ = 450 x 10⁻⁸ m

tensile strength F / A = 311 x 10⁶ N / m²

F = A x 311 x 10⁶

= 450 x 10⁻⁸ x 311 x 10⁶

= 139950 x 10⁻²

= 1399.5 N  .

Answer:

Explanation:

Given

speed of water balloon = 8.31m/s

Height of building = 23.0m

Required

Horizontal distance

First we need to get the time using the equation of motion

S  = ut + 1/2at²

23 = 0+1/2(9.81)t²

23 = 4.905t²

t² = 23/4.905

t² = 4.689

t = √4.689

t = 2.17secs

Next is to get the horizontal direction expressed as:

Sh = Vxt

Sh =  8.31 * 2.17

Sh = 17.99m

Sh ≈ 18m

Hence the horizontal distance of the object before striking the ground is approximately 18m

Answer:

a) 4.8*10^-19 C

b) 3

Explanation:

We know that

F = ma

Also, recall that a = v²/r and F = qvB

Substituting this in the first equation, we have

qvB = mv²/r, since we're looking for q, we make it the subject of the formula and solve for it.

q = mv²/rvB

q = mv/rB

q = [2.66*10^-26 * (5*10^6)] / 0.231 * 1.2

q = 1.33*10^-19 / 0.2772

q = 4.8*10^-19 C

Ratio between the charge and the electron is q/c =

4.8*10^-19 / 1.6*10^-19 = 3

Therefore, the ratio between the charge and electron is 3

Answer:

The color of an object is the wavelength of light that it reflects.

Answer:

25776J

Explanation:

Recall that heat lost/gained is obtained from

H=mcθ

H= heat lost/gained

m= mass of water = 0.0100 kg

c= 4200 J/kg°C

θ = temperature

Heat gained by the water in rising to 100°

H=  0.0100 * 4200 * (100-22)

H= 3276 J

Latent heat of vaporization of water = mL

Latent heat of vapourization = 0.0100*(22.5*10^5)=22500J

Heat lost by iron = heat gained by water

total heat gained by water =

22500+3276=25776J

Answer:

The total kinetic energy must be greater than the momentum of either ball

Explanation:

In order to solve this problem, we must clarify the following conditions, the balls are in motion that is, there is kinetic energy, the kinetic energy is a scalar magnitude, therefore this energy is greater than zero.

But however momentum is equal to zero, momentum is a vector quantity, that is, these velocities have a direction, momentum is defined as the product of mass by Velocity.

P = m*v (momentum lineal)

where:

P = lineal momentum [kg*m/s]

m = mass [kg]

v = velocity [m/s]

Since the masses of the balls are equal, we have:

m1 = m2

therefore:

m1*v1 + (m2*v2) = 0 (total momentum)

For the sum to be equal to zero, besides the equivalation of the masses, the velocities must also be equal, but the velocities must be of opposite sign, to meet equality to zero.

m1*v1 - m2*v2 = 0

And the kinetic energy of a body is defined by means of the following equation

Ek = 0.5*m*v²

Since the magnitude of the velocities is greater than zero, so that there is movement, we can say that the kinetic energy is much greater than zero, as well as greater than the total linear momentum

Answer:

3.2m/s

Explanation:

Given parameters:

Initial velocity  = 1.125m/s

Height of fall  = 0.45m

Unknown:

Final velocity  = ?

Solution:

To solve this problem, we have to look at our given parameters and compare to the appropriate motion equation.

  we have been given;   u (initial velocity) and height of fall (h)

Since this body falls under acceleration due to gravity, g = 9.8m/s²

Now, we use;

           V²  = U² + 2gh

 where V is the final velocity

       Input the parameters and solve;

          V² = 1.125² + (2 x 9.8 x 0.45)

          V = 3.2m/s

Answer:

The other piece is moving at 170 m/s.

Explanation:

To find the speed of the second piece can be found by conservation of linear momentum:  

[tex] p_{i} = p_{f} [/tex]

[tex] m_{1}v_{1} = m_{2}v_{2} + m_{3}v_{3} [/tex]

Where:

m₁: is the rocket's mass = 0.5 kg      

m₂ = m₃: is the mass of the two equal pieces = 0.25 kg

v₁: is the rocket speed = 90 m/s

v₂: is the speed of the first piece = 10 m/s

v₃: is the speed of the second piece =?

[tex] 0.5*90 = 0.25(10 + v_{3}) [/tex]

[tex] v_{3} = \frac{45}{0.25} - 10 = 170 m/s [/tex]

Therefore, the other piece is moving at 170 m/s.

I hope it helps you!                                                                   

Answer:

4m/s^2

Explanation:

According to newton's second law of motion:

F= ma

a= F/m

F =220N

m =55kg

a= 220/55

= 4m/s^2

Answer: there are multiple

Explanation:

light from a torch, the heat from a fire, and the sound of a police siren. You cannot hold, taste, or smell these things. They are not types of matter, but forms of energy.

Answer:

m = m_o/e

Explanation:

The rocket equation is given as;

m(dv/dt) = -v_ex(dm/dt)

v_ex is the exhaust velocity

Now, formula for momentum is;

p = mv

Differentiating with respect to time, we have;

dp/dt = m'v + mv'

Where;

m' is mass rate

v' is rate of change in velocity

Since we are dealing with exhaust velocity and momentum(p) is Maximum when v = v_ex then mv' can also be written as: -m'v_ex.

Thus;

dp/dt = m'v - m'v_ex

dp/dt = m'(v - v_ex)

Now, from the rocket equation we dt will cancel out to give;

-dv/v_ex = dm/m

Integrating both sides;

-∫dv/v_ex = ∫dm/m

This gives;

-v/v_ex = In(m/m_o)

Since momentum(p) is Maximum when v = v_ex

Thus;

-v/v = In(m/m_o)

-1 = In(m/m_o)

e^(-1) = m/m_o

m = m_o(e^(-1))

m = m_o/e

Answer:

Explanation:

efficiency of carnot engine = (Q₁ - Q₂) / Q₁ = (T₁ - T₂) / T₁

Q₁ = heat absorbed , Q₂ = heat rejected

T₁ = Temperature of source = 525 + 273 = 798 K

T₂ = Temperature of sink = 50 + 273 = 323 K

efficiency = (798 - 323) / 798

= 475 / 798 = .595

(Q₁ - Q₂) / Q₁ = .595

(250 - Q₂) / 250 = .595

250 - Q₂ = 148.75

Q₂ = 101.25 kJ

Heat rejected = 101.25 kJ .

output work = Q₁ - Q₂ = 250 - 101.25 = 148.75 kJ / s

power = 148.75 kJ /s

Answer: the coefficient of restitution of the ball for a collision with asphalt=0.95

Explanation:

Initial height of the bounce from the ball, h  =2.47m

height of the 5th bounce of the ball , h₁= 1.51m

Making e the coefficient of the restitution, then the height covered by the ball after the 5th bounce is

h₁= e²ⁿh

Where n = 5

h₁= e²⁽⁵⁾h

e¹⁰=h₁/h

e¹⁰=1.51/2.47

e= (1.51/2.47)¹/¹⁰

e=0.95198≈ 0.95

Therefore, the coefficient of restitution of the ball for a collision with asphalt is 0.95

a= vf - vi/t

a= 60-0/10

a= 60/10

a= 6 m/s^2

Answer:

6 km/hr/s

Explanation:

Answer:

3.69m/s²

Explanation:

Using the formula;

S = ut + 1/2gt²

Where;

S = distance (m)

u = initial velocity (m/s)

t = time (s)

g = accelerate due to gravity (m/s)

Based on the information provided, S = 73.3m, u = 4.5m/s, t = 5.2s, g= ?

73.3 = (4.5 × 5.2) + 1/2 (g × 5.2²)

73.3 = 23.4 + 1/2 (27.04g)

73.3 = 23.4 + 13.52g

73.3 - 23.4 = 13.52g

49.9 = 13.52g

g = 49.9/13.52

g = 3.6908

g = 3.69m/s²

Answer:

4. Water stored in the tank has potential energy only.

Explanation:

when water begins to move the potential energy is converted into kinetic but until it is being used it has potential energy only.

I've attached a sketch of what I interpret the situation to be. It seems to me that you have to find the height of the projectile above the mountain's peak, assuming it actually does hit the ship on the other side. (Note that the sketch is not drawn to-scale. I don't mean to suggest that the projectile reaches its maximum height directly above the mountain.)

Compute the horizontal and vertical components of the velocity:

[tex]v_{i,x}[/tex] = (2.55 x 10² m/s) cos(72.4º) ≈ 77.1 m/s

[tex]v_{i,y}[/tex] = (2.55 x 10² m/s) sin(72.4º) ≈ 243 m/s

The projectile's horizontal and vertical positions at time t from its launching point are

x = [tex]v_{i,x}[/tex] t

y = [tex]v_{i,y}[/tex] t - 1/2 (9.81 m/s²) t²

Find the time it takes for the projectile to travel the distance from the first ship to the mountain's peak:

2.47 x 10³ m = (77.1 m/s) t

t = (2.47 x 10³ m) / (77.1 m/s)

t ≈ 32.0 s

Find the vertical position at this time:

y = (243 m/s) (32.0 s) - 1/2 (9.81 m/s²) (32.0 s)²

y ≈ 2750 m = 2.75 x 10³ m

Take the difference of this height and the height of the mountain:

2.75 x 10³ m - 1.77 x 10³ m = 0.980 x 10³ m = 9.80 x 10² m

Answer:

No non-conservative forces, such as friction, act between objects within the system

Explanation:

The law of conservation of mechanical energy in a closed system states that;'The total amount of mechanical energy, in a closed system in the absence of non-conservative forces, such as friction, remains constant.' Non-conservative forces  cause energy to be lost from the system, this lost energy can't be gotten back

This implication of this is that energy can not disappear. Kinetic energy can be converted into potential energy and vice-versa in accordance with this principle.

Answer:

In stage 3 so the answer is D

Answer:

It's D. in stage 3 of non-rapid-eye-movement sleep

Explanation:

**PLATO**  "NREM-3 is when a person is in deep sleep and it lasts about 30 minutes. The person experiences slow breathing and pulse rates and limp muscles, and is difficult to wake. This stage is sometimes called delta sleep, because the brain produces slow delta waves."

Answer:

The speed of the bullet before the impact is 556.5 m/s

Explanation:

Given;

mass of the wooden block, m₁ = 872 g = 0.872 kg

initial velocity of the wooden block, u = 0

mass of the bullet, m₂ = 15.6 g = 0.0156 kg

distance traveled by the block-bullet system after impact, d = 6.5 m

coefficient of kinetic friction, μ = 0.75

Work done by friction on the system after impact is given by;

W = (m₁ + m₂)μg x d

kinetic energy of the system after impact is given by;

K.E = ¹/₂(m₁ + m₂)v²

Apply work energy theorem;

(m₁ + m₂)μg x d = ¹/₂(m₁ + m₂)v²

μg x d = ¹/₂v²

v² = 2μg x d

v = √(2μg x d)

v = √(2 x 0.75 x 9.8 x 6.5)

v = 9.78 m/s

The speed of the bullet before impact is calculated by applying principle of conservation of linear momentum;

m₁u₁ + m₂u₂ = v(m₁ + m₂)

0.872(0) + 0.0156u₂ = 9.78(0.872 + 0.0156)

0 + 0.0156u₂ = 8.681

u₂ = 8.681 / 0.0156

u₂ = 556.5 m/s

Therefore, the speed of the bullet before the impact is 556.5 m/s

Answer:

vf = 3 m/s

Explanation:

       [tex]\Delta K = \frac{1}{2}* m* (v_{f}^{2} -v_{o} ^{2} ) = W_{Ffr} (1)[/tex]

Replacing for the givens, we get:

[tex]\Delta K = \frac{1}{2}* 20kg* (v_{f}^{2} -(5 m/s) ^{2} ) = -20 m * 8 N (2)[/tex]

[tex]v_{f} = \sqrt{-16 (m/s)2 + 25 (m/s)2} = \sqrt{9 (m/s2)} = 3 m/s[/tex]

vf = 3 m/s

Am assuming the  B-field has an rms strength of 1.10×10−10T which was omitted

Answer:  E=1.686 x10⁻⁸J/hr

Explanation:

Intensity for electromagnetic wave is given as

I= cε₀(Emax)²....... equation 1

Also

B=Emax/c   ....... equation 2

puting the value of B in equation 2 in equation 1 becomes

I= cε₀(Emax)²

I= c³ε₀B²

where

c = speed of light = 3 X 10⁸m/s

ε₀=permittivity of free space = 8.85x 10-12 F m-1

B=1.10×10−10T

I= (3 X 10⁸m/s)³ X (8.85 X 10⁻12F/m) x(1.10×10−10T)²

I=2.891 X 10⁻⁶ W/m²

Energy per unit hour

E= IAt

= 2.891 X 10⁻⁶ W/m² x πr²x 3600

2.891 X 10⁻⁶ W/m² x 3.142 x ( 1.80 x 10⁻³/2) x(3600/1hr)

E=1.686 x10⁻⁸J/hr

The total energy transported per hour will be 6.62 × 10⁻⁹J

The Intensity for an electromagnetic wave is given by:

I = cε₀E₀²

where c is the speed of light, and

E₀ is the maximum value of the electric vector

Also

B = E/c  

where B is the magnetic field

Therefore:

I= cε₀E₀²

I= c³ε₀B²

Given that the magnetic field is:

B = 1.10×10⁻¹⁰ T

I= (3 X 10⁸m/s)³ X (8.85 X 10⁻12F/m) x(1.10×10−10T)²

I=2.891 X 10⁻⁶ W/m²

Energy transported per unit hour

E= IAt

where A is the area

and t is the time = 1hr = 3600s

E = 2.891 × 10⁻⁶  × πr² × 3600

E = 2.891 X 10⁻⁶ ×  3.14 × ( 1.80 x 10⁻³/4)² x (3600)

E = 6.62 × 10⁻⁹J

Learn more about electromagnetic waves:

https://brainly.com/question/13803241?referrer=searchResults

Answer:

More electrons become free due to the potential which are charge carriers. More the charge carriers, more the current.

Current causes a heating effect. Resistance of lead decreases/ n increases [I=nAve]. Current increase

Explanation: