A swimmer swims 20 m in 40 s. What is swimmer’s average speed?

Answer:

The value is [tex]v = 7.89 \ m/s[/tex]

Explanation:

From the question we are told that

  The mass  of the object is [tex]m = 0.414 \ kg[/tex]

   The force is [tex]F = 2.08 \ N[/tex]

  The time taken is  [tex]t = 1.57 \ s[/tex]

Generally the force acting on the object according to Newton's second law is

        [tex]F = \frac{ m (v -u )}{t}[/tex]

=>     [tex]v = \frac{F * t}{m} + u[/tex]

Here u is the initial velocity with value  0 m/s since the object was initially at rest

        [tex]v = \frac{2.08 * .57}{0.414 } + 0[/tex]

     [tex]v = 7.89 \ m/s[/tex]

Answer:

my answer is in explanation below

Explanation:

You would convince him by saying the pattern adds elevation to the shoe therefore causing more friction.

(If it's wrong, I am sorry, I'm not in college)

(If it's right, can I get that brainliest?)

Answer:

3 m/s

Explanation:

We can solve with kinematics or with energy.

Using kinematics, and taking down to be positive, we're given:

Δy = 0.45 m

v₀ = 0 m/s

a = 10 m/s²

Find: v

v² = v₀² + 2aΔy

v² = (0 m/s)² + 2 (10 m/s²) (0.45 m)

v = 3 m/s

Or, we can use energy.

PE = KE

mgh = ½ mv²

v = √(2gh)

v = √(2 × 10 m/s² × 0.45 m)

v = 3 m/s

Answer:b

Explanation:

I got the answer right

The main advantage of using nuclear power over natural gas to generate the electricity that nuclear power does not contribute to climate change, therefore the correct answer is option B.

It is a particular kind of power plant where electricity is produced using a nuclear reactor that may use nuclear fusion or nuclear fission .

When a radioactive substance undergoes a nuclear reaction, a tremendous quantity of energy is produced .

As given in the problem , we have to find out what is an advantage of using nuclear power over natural gas to generate electricity .

Option B is the proper response , since employing nuclear power instead of natural gas to produce electricity has the advantage of not causing the climate change .

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Answer:

The speed of the ball is 7.36 m/s

Explanation:

Constant Acceleration Motion

It happens when the velocity of an object changes by an equal amount in every equal period of time.

Being a the constant acceleration, vo the initial speed, vf the final speed, and t the time, the following relation applies:

[tex]v_f=v_o+at[/tex]

Since the situation corresponds to a vertical motion, the acceleration is g=9.8 m/s^2.

The ball is thrown downward at vo=0.5 m/s. Its speed at t=0.7 seconds is

[tex]v_f=0.5+9.8\cdot 0.7[/tex]

[tex]v_f=7.36\ m/s[/tex]

The speed of the ball is 7.36 m/s

Note: There is no use of the height it was released from

The correct expression for the mass m of the bone is m=Fs-Fb/a.

The force is defined as the shear stress or pressure applied per unit area.

A big dog B and a small dog S are pulling horizontally in opposite directions on a large bone. The bone’s mass is m, the big dog’s leftward force magnitude is Fb and the small dog’s rightward force magnitude is Fs. The bone accelerates to the right along the table with no friction.

Across the bottom is green grass. In the center, there is a brown table with a large bone on top. To the left is a black outline of a large dog facing rightwards that is pulling leftwards on the bone. To the right is a black outline of a small dog facing leftwards that is pulling rightwards on the bone. The small dog stands on a grey box. Across the bottom is green grass.

Two dogs pulling on a large bone. Big dog and small dog images courtesy of pixabay. Consider rightward as the positive direction.

The net force acting on bone will be

F = Fs -Fb

From the Newton's second law of motion, Force  = mass x acceleration

F = ma

m = F/a

m = Fs-Fb/a

Thus, correct expression for the mass m of the bone is m=Fs-Fb/a.

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Answer:

The breaking strength of the string is 717.19 N

Explanation:

Given;

initial tension on the string, T₁ = 53.9 N

initial radius of the string, r₁ = 2.59 m

initial speed of the rock, v₁ = 21.8 m/s

final radius of the string, r₂ = 1.23 m

final speed of the rock, v₂ = 54.8 m/s

the final tension on the string = breaking strength, T₂ = ?

Apply centripetal force equation due to inward motion;

[tex]T= \frac{mv^2}{r}\\\\Tr = mv^2\\\\m =\frac{Tr}{v^2}\\\\ \frac{T_1r_1}{v_1^2} = \frac{T_2r_2}{v_2^2}\\\\T_2 = \frac{T_1r_1v_2^2}{r_2v_1^2}\\\\ T_2 = \frac{(53.9)(2.59)(54.8)^2}{(1.23)(21.8)^2}\\\\ T_2 = 717.19 \ N[/tex]

Therefore, the breaking strength of the string is 717.19 N

Hi! Compressibility is the capacity of something to be flattened or reduced in size by pressure. I hope this helps you! Good luck and have a great day. ❤️

Answer:

Explanation:

it is C

Answer:

2.385 m/s

Explanation:

Here there is a transformation of potential energy of the water at the top to Kinectic energy at the hole

This can be expressed as

Potential energy= Kinect energy

mgh= 1/2m v²

Where m= mass of water

h= Lenght below the level of the water that is in the tank.

v= the speed of the water as it leaves the hole

g= acceleration due to gravity= 9.81m/s

Here there is 'm' at both sides which can cancelled beach other out.

Then we have

gh= ¹/₂v²

making v² subject of the formular

v²=gh/(¹/₂)

v=√(2gh)

V=√2g h

V= √(2×9.81×0.29)

V=2.385 m/s

Therefore, the speed of the water as it leaves the hole is 2.385 m/s

Answer:

The object travels a distance of 40 meters before it stops.

Explanation:

A body moves with constant acceleration motion or uniformly accelerated rectilinear motion (u.a.r.m) when the trajectory of the mobile is a straight line and its speed varies the same amount in each unit of time.

Torricelli's equation relates the speed to the space traveled by the body in u.a.r.m. To calculate the velocity of a body as a function of space, the expression is used:

[tex]v^{2} =v0^{2} +2*a*d[/tex]

Where :

In this case:

Replacing:

[tex](0\frac{m}{s} )^{2} =(20 \frac{m}{s} )^{2} +2*(-5\frac{m}{s^{2} }) *d[/tex]

Solving:

[tex]0\frac{m^{2} }{s^{2} } =400 \frac{m^{2} }{s^{2} } -10\frac{m}{s^{2} } *d[/tex]

[tex]0\frac{m^{2} }{s^{2} } -400 \frac{m^{2} }{s^{2} } = -10\frac{m}{s^{2} } *d[/tex]

[tex]-400 \frac{m^{2} }{s^{2} } = -10\frac{m}{s^{2} } *d[/tex]

[tex]\frac{ -400 \frac{m^{2} }{s^{2} }}{ -10\frac{m}{s^{2} }} = d[/tex]

40 m= d

The object travels a distance of 40 meters before it stops.

Answer:

The coordinates of the 4.0-kg mass must be [tex](x,y) = (-3\,m,-6\,m)[/tex].

Explanation:

We have a system formed by three particles with known masses and locations with respect to origin. The location of the center of mass is calculated by means of weighted means. That is:

[tex]\bar x = \frac{\Sigma\limits_{i=1}^{n}\,x_{i}\cdot m_{i}}{\Sigma\limits_{i=1}^{n}m_{i}}[/tex] (Eq. 1)

[tex]\bar y = \frac{\Sigma\limits_{i=1}^{n}\,y_{i}\cdot m_{i}}{\Sigma\limits_{i=1}^{n}m_{i}}[/tex] (Eq. 2)

Where:

[tex]\bar x[/tex], [tex]\bar y[/tex] - Coordinates of the center of mass of the system, measured in meters.

[tex]x_{i}[/tex], [tex]y_{i}[/tex] - Coordinates of the i-th particle, measured in meters.

[tex]m_{i}[/tex] - Mass of the i-th particle, measured in kilograms.

If we know that [tex]m_{1} = 3\,kg[/tex], [tex]m_{2} = 1\,kg[/tex], [tex]m_{3} = 4\,kg[/tex], [tex]x_{1} = 0\,m[/tex], [tex]x_{2} = 12\,m[/tex], [tex]\bar x = 0\,m[/tex], [tex]y_{1} = 8\,m[/tex], [tex]y_{2} = 0\,m[/tex] and [tex]\bar y = 0\,m[/tex], the location of the 4.0 kg mass is:

[tex]\frac{(3\,kg)\cdot (0\,m)+(1\,kg)\cdot (12\,m)+(4\,kg)\cdot x_{3}}{3\,kg+1\,kg+4\,kg} = 0\,m[/tex]

[tex]12+4\cdot x_{3} = 0[/tex]

[tex]x_{3} = -3\,m[/tex]

[tex]\frac{(3\,kg)\cdot (8\,m)+(1\,kg)\cdot (0\,m)+(4\,kg)\cdot y_{3}}{3\,kg+1\,kg+4\,kg}= 0\,m[/tex]

[tex]24+4\cdot y_{3} = 0[/tex]

[tex]y_{3} = -6\,m[/tex]

The coordinates of the 4.0-kg mass must be [tex](x,y) = (-3\,m,-6\,m)[/tex].

The coordinates of the 4kg mass so that the center of mass of the three-mass system will be at the origin is (-3,-6)

The coordinates of the 3kg mass are (0.0 m, 8.0 m)

and the coordinates for the 1kg mass are  (12 m, 0.0 m)

Let the coordinates of the 4kg mass be (x,y)

The final coordinates of the center of mass of the system are (0,0),

so the equation for x-coordinate is given by:

[tex]0=\frac{3\times0+1\times12+4\times x}{3+1+4}[/tex]

12 + 4x = 0

x = -3

the equation for y-coordinate is given by:

[tex]0=\frac{3\times8+1\times0+4\times y}{3+1+4}[/tex]

24 + 4y = 0

y = -6

So, the coordinates of the 4kg mass are (-3,-6)

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Answer:

C pollutants

Explanation:

Pollutants are dangerous substances in the ecosystem that are harmful to its organisms. They are contaminants and effluents that leads to pollution in the environment.  

Answer:

c

Explanation:

Answer: Height = 0.45m

Explanation:

According to the conservation of energy, When there are no interactions outside a system ie  neglecting air resistance,The change in kinetic energy is equal to the change in potential energy in a closed system.

Therefore the kinetic energy decrease, the potential energy increases, and  decreases for increase in Kinetic energy

an is represented by the formulae

ΔKinetic energy + ΔPotential energy = 0

ΔKinetic energy = -ΔPotential energy ( where negative sign represent decrease as kinetic energy increases.

ΔK.E=ΔP.E

420J- 220J= mgh

mass = 45kg

g =gravitational acceleration =9.8 m/s^2

200J = 45 X 9.8 X h

h = 200/45 x 9.8 /= 0.45m

Answer:

m = 0.172 [kg]

Explanation:

To solve this problem we must use the expression of thermal energy that relates the heat to the mass, the specific heat, and the temperature differential.

Q = m*Cp*(T_f - T_i)

where:

m = mass [kg]

Cp = specif heat = 126 [J/kg*C]

Q = 5000 [J]

T_f = final temperature = 250 [C]

T_i = initial temperature = 20 [C]

m = Q/ (Cp*(T_f - T_i))

m = 5000/ (126*(250 - 20))

m = 0.172 [kg]

Answer:

d. collection of photos taken by a person while moving around different places

Answer:

Moving object at equal time intervals

Answer:

9.63 m

Explanation:

We know that

Δx = vt.

Therefore, v = Δx / t

v = 5 / 0.378

v = 13.23 m/s

h = ½gt, so that

h = ½ * 9.8 * 0.378²

h = 4.9 * 0.1429

h = 0.7 m

Finally, using the law of conservation of energy, we know that

½mv² = mg(H - h)

½v² = g(H - h)

½v²/g = H - h, substituting the values and solving, we have

(½ * 13.23²) / 9.8 = H - 0.7

(½ * 175) / 9.8 = H - 0.7

87.5 / 9.8 = H - 0.7

8.93 = H - 0.7

H = 8.93 + 0.7

H = 9.63 m

Answer:

Explanation:

weight of the car mg = m g

frictional force acting on the car = μ mg where μ is coefficient of friction

= m μ g

This force provides centripetal force , hence

m μ g  = m v² / R

μ = v² / rg

= 22 x 22 / 65 x 9.8

= .759  

Answer:

D

Explanation:

Answer:

Hydroelectric power plants

Explanation:

This is because hydropower is a form of renewable energy that uses water stored in dams, rivers to create electricity

Answer:the potential difference Vb − Va = -3 V

Explanation:

The potential difference Vb − Va s given by

Vb − Va=  Capacitance / Charge + current x resistance - Electromotive force

Vb − Va=Q/C + I X R - E

V=Q / C=(12 x 10^-3) / (3 x 10^-3)

=0.012/0.003ss

=4V

alsoV=  1R = 2.0 x 10^-3 x 4 x 10^3

=0.002 X 4000

=8

Vb − Va= 4V + 8V- 15V

= -3V

Therefore, the potential difference Vb − Va = -3 V

Answer:

Explanation:

Force F = GMm / R²

mass of the sun M = 1.99 x 10³⁰ kg

mass of the earth = 5.97 x 10²⁴ kg

value of G = 6.67 x 10⁻¹¹

for perihelion point R = 1.48 x 10¹¹ m

Force = 6.67 x 10⁻¹¹ x  1.99 x 10³⁰ x 5.97 x 10²⁴ / ( 1.48 x 10¹¹ )²

= 36.17 x 10²¹ N  

for aphelion point R = 1.52 x 10¹¹ m

Force = 6.67 x 10⁻¹¹ x  1.99 x 10³⁰ x 5.97 x 10²⁴ / ( 1.52 x 10¹¹ )²

= 34.29  x 10²¹ N  

Answer:

17.65N

Explanation:

We know that the relationship for the impulse and momentum is given as

Ft=mv

given data

mass m=0.15kg

t= 51ms= 26.5/1000= 0.051seconds

velocity v1= 21m/s

Velocity v2=15m/s

substituting in the expression we have

Ft=m(v1-v2)

make F subject of formula we have

F=m(v1-v2) /t

F=0.15(21-15)/0.051

F=0.15*6/0.051

F=0.9/0.051

F=17.65N

This question involves the concepts of momentum and impulse.

The average force of the bat on ball is "17.65 N".

According to Impulse Equation the change in momentum is equal to the product of applied force and time of contact. Mathematically:

[tex]\Delta P=F\Delta t\\\\F=\frac{m\Delta v}{\Delta t}[/tex]

where,

Therefore,

[tex]F=\frac{(0.15\ kg)(6\ m/s)}{0.051\ s}[/tex]

F = 17.65 N

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Answer:

9000 J

Explanation:

weight of bullet = 100 g

length of gun barrel = 0.6m

A) determine the work done by the gas on the bullet as the bullet travels the length of the barrel

The work done is an integral of force over distance in this scenario

lets represent the force using some constants ( arbitrary )

Fx = a  + bx + cx^2

where : a = 15000,  b = 10000, c = - 25000

hence work done ( W ) = [tex]ax_{f } + \frac{bx^{2} _{f} }{2} + \frac{cx^{3} _{f} }{3}[/tex]

where ; xf = 0.6

hence work done(W)

= 15000(0.6) + [(10000*0.6^2)/2] + [(-25000*0.6^3)/3]

 = 9000 J

Answer:

Cccccccc GIVE BRAINLYEST PLEASE

Answer: It´s c-skeletal

Explanation:

Answer:

Explanation:

According to law of conservation of momentum

(m1+m2)v = m1u1+m2u2

Let m1 and m2 be the masses

u1 and u2 be their respective velocities

v is the velocity of combined objects

Given

m1 =60kg

m2 = 40kg

v =0 m/s

u2 -  u1 = 60 ............ 1

0 = 60u1 + 40u2 = 0 .......... 2

From 1: u2 = 60+u1

Substitute into 2:

60u1 + 40(60+u1) = 0

60u1 +2400 +40u1 = 0

100u1 = -2400

u1 = -2400/100

u1 = -24m/s

Hence the speed of the 60 kg mass is 24m/s (in the negative direction)