please help, i only need help with 2,5, and 7

Answer:

The hikers average speed due north is 0.2 km per minute.

Explanation:

Speed is the ratio of distance moved by a body to the time taken.

i.e speed = [tex]\frac{distance}{time}[/tex]

Since the hiker walks due north and due west, then his average speed due north can be determined by;

Average speed = [tex]\frac{total distance due north}{total time taken}[/tex]

Total distance due north = 5.0 + 7.0

                                  = 12.0 km

Total time taken = 20 + 40

                           = 60 minutes

                           = 1 hour

Average speed due north= [tex]\frac{12}{60}[/tex]

                          = [tex]\frac{1}{5}[/tex]

                          = 0.2

Average speed due north = 0.2 km/minute

The hikers average speed due north is 0.2 km per minute.

Answer:

[tex]a=5.34\ m/s^2[/tex]

Explanation:

Given that,

Initial velocity of a sprinter, u = 0

He runs a distance of 24m in 3 seconds.

We need to find his acceleration. Let a be his acceleration. Using second equation of kinematics to find it.

[tex]s=ut+\dfrac{1}{2}at^2\\\\24=0+\dfrac{1}{2}a(3)^2\\\\a=\dfrac{24\times 2}{9}\\\\a=5.34\ m/s^2[/tex]

So, the acceleration of the sprinter is [tex]5.34\ m/s^2[/tex].

The acceleration of the sprinter from rest to his top speed is 5.33m/s²,

Given the data in the question

Since the sprinter starts from rest,

Acceleration; [tex]a = \ ?[/tex]

To determine the acceleration of the sprinter, we use the second equation of motion:

[tex]s = ut + \frac{1}{2}at^2[/tex]

Where s is distance covered, u is initial velocity, a is acceleration and t is time.

We substitute our given values into the equation

[tex]24m = [0 * 3s] + [\frac{1}{2} * a * (3s)^2]\\\\24m = \frac{1}{2} * a * 9s^2\\\\24m = a * 4.5s^2\\\\a = \frac{24m}{4.5s^2} \\\\a = 5.33m/s^2[/tex]

Therefore, the acceleration of the sprinter from rest to his top speed is 5.33m/s²

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Answer:

2.97 meters

9.85 m/s^2

Explanation:

Given that :

Period (T1) = 3.45 seconds

When length , l is shortened by 1m, period (T2) = 2.81 seconds

Using the relation :

T = 2π√l/g

g = acceleration due to gravity

T1 = 2π√L/g - - - - (1)

Period 2:

x = shortened length = 1m

T2 = 2π√L-x/g - - - (2)

Square both sides

T1² = (2π)² L/g - - - (3)

T2² = (2π)² L-x/g - - (4)

Divide 3 and 4

(T2/T1)² = (L-x) / L

(2.81/3.45)^2 = (L - 1) / L

0.6633984 = (L - 1) / L

0.6633984L = L - 1

0.6633984L - L = - 1

−0.336601L = - 1

L = 1 / 0.336601

L = 2.9708764

Length = 2.97 meters

Acceleration due to gravity :

g = L(2π/T1)^2

g = 2.97(2π / 3.45)^2

g = 2.97 * 3.3168172

g = 9.8509

g = 9.85 m/s^2

g

Answer:

Im not fully corrrect but I would say C

Explanation:

Answer:

E = 50850[kJ]

Explanation:

To boil the water we must use the latent heat of vaporization. Also we need to multiply this value by the mass of the water.

[tex]E=m*H_{v}[/tex]

Where:

E = energy produced by heat [J]

m = mass = 225 [kg]

Hv = 226000 [J/kg]

[tex]E = 225*226000\\E = 50850000 [J]\\E=50850[kJ][/tex]

Answer:

Magnets work by using Earth's magnetic pull.

Explanation:

Magnets move objects because they are made of steel or metal. And for that reason, they can stick to objects that are metal.

Answer:

The speed of a wave would be 18 with a wavelength of 2 m and a frequency of 9 Hz.

Answer:

There are six major nutrients: Carbohydrates (CHO), Lipids (fats), Proteins, Vitamins, Minerals, Water.

Explanation:

Answer:

number 4

Explanation:

The reflection of light happens when the light bounces off the reflecting surface. That is described by the last (bottom) schematics.

Therefore, select answer number 4.

Answer:

72.11

Explanation:

Using the formula:

R^2=A^2+B^2

R= √ A^2+B^2

Where R= displacement

A=40km

B=60km

R= √ 40^2+60^2

R= √ 1600+3600

R= √ 5200

R=72.11km

Answer:

uniform acceleration motion is a motion with constant acceleration.

Answer:

b. at the top

Explanation:

At the top of the climb, the vertical velocity of Jeff's throw has a value of zero.

Vertical velocity in this instance is acting against the acceleration due to gravity.

Answer:

because of Friction is always present.

technically usually the warmer object/substances particles move master which causes friction among the particles plus the kinetic energy being converted to thermal energy, so i would say the hand.

Answer:

[tex]P=203.3819375kg.m/s\\P\approx203.4kg.m/s[/tex]

[tex]\theta=6.4541\textdegree North East\\\theta\approx6.5\textdegree North East[/tex]

Explanation:

From the question we are told that

Mass of first jogger [tex]M=69kg[/tex]

Speed[tex]v_1=1.6m/s[/tex]

Direction [tex]d= East[/tex]

Mass of 2nd jogger [tex]M=63kg[/tex]

Speed [tex]v_2=1.5m/s[/tex]

Direction [tex]d= 14\textdegree north[/tex]

Generally equation for momentum along the the horizontal is mathematically given as

[tex]P_x=m_1v_1 +m_2v_2cos\theta[/tex]

[tex]P_x=(69)*(1.6) +(63)*(1.5)cos14[/tex]

[tex]P_x=202.0929461kg.m/s[/tex]

Generally equation for momentum along the the vertical is mathematically given as

[tex]P_y=m_2v_2cos\theta[/tex]

[tex]P_x=22.86161913kgm/s[/tex]

a)Generally the magnitude of momentum is mathematically given by

[tex]P=\sqrt{(P_x)^2+(P_y)^2}[/tex]

[tex]P=\sqrt{(202.0929461)^2+(22.86161913)^2}[/tex]

[tex]P=\sqrt{41364.21249}[/tex]

[tex]P=203.3819375kg.m/s[/tex]

[tex]P\approx203.4kg.m/s[/tex]

b) Generally the angle [tex]\theta[/tex] is mathematically given by

[tex]\theta=tan^-^1\frac{py}{px} \\[/tex]

[tex]\theta=tan^-^1\frac{22.86161913}{202.0929461}[/tex]

[tex]\theta=tan^-^1(0.1131242805)[/tex]

[tex]\theta=6.4541\textdegree North East[/tex]

Answer:

It represents the amount of speed per time or (x) for speed (y) for time so the slope would be like y/x

Answer:

A. White light is the absence of all color.

Explanation:

It is false that white light is the absence of all color. In fact, white light is the presence of all colors in the spectrum.

Electromagnetic waves are waves that do not require any material medium for propagation. It is the interaction of electric and magnetic fields.

Answer:

D. Upward force on the shuttle

Explanation:

The hot gas from space shuttles released downward causes an upward force on the shuttle and propels it up the more.

Answer:

16Hz

Explanation:

Given parameters:

Speed of sound  = 400m/s

Wavelength  = 25m

Unknown:

Frequency of the wave  = ?

Solution:

To solve this problem;

      V  = F ∧  

V is the velocity

F is the frequency

∧ is the wavelength

      400  = F x 25

        F  = 16Hz

Answer:

16 hertz... I got it right on study-island

Explanation:

Answer: Ima have to say broccoli

Explanation:

Answer:

D. 90km/hr due West

Explanation:

Given parameters:

Displacement  = 1215km

Time  = 13.5hr

Unknown:

Velocity  = ?

Solution:

Velocity is the displacement divided by the time taken;

   Velocity  = [tex]\frac{displacement}{time}[/tex]   = [tex]\frac{1215km}{13.5hr}[/tex]   = 90km/hr

Velocity is 90km/hr due West

Answer:

12 m

Explanation:

From the question given above, the following data were obtained:

Mass (m) of bag = 25 kg

Potential energy (PE) = 2940 J

Height (h) =?

Objects carried to a particular height will always experience an acceleration due to gravity of 9.8 m/s².

With the above in mind, we can obtain the height to which the load is lifted to as shown below:

Mass (m) of bag = 25 kg

Potential energy (PE) = 2940 J

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

Height (h) =?

PE = mgh

2940 = 25 × 9.8 × h

2940 = 245 × h

Divide both side by 245

h = 2940 / 245

h = 12 m

Therefore, the worker lifts the load to a height of 12 m.

The principles which allow aircraft to fly are also applicable in car racing. The only difference being the wing or airfoil shape is mounted upside down producing downforce instead of lift. The Bernoulli Effect means that: if a fluid (gas or liquid) flows around an object at different speeds, the slower moving fluid will exert more pressure than the faster moving fluid on the object. The object will then be forced toward the faster moving fluid. The wing of an airplane is shaped so that the air moving over the top of the wing moves faster than the air beneath it. Since the air pressure under the wing is greater than that above the wing, lift is produced. The shape of the Indy car exhibits the same principle. The shape of the chasis is similar to an upside down airfoil. The air moving under the car moves faster than that above it, creating downforce or negative lift on the car. Airfoils or wings are also used in the front and rear of the car in an effort to generate more downforce. Downforce is necessary in maintaining high speeds through the corners and forces the car to the track. Light planes can take off at slower speeds than a ground effects race car can generate on the track. An Indy ground effect race car can reach speeds in excess of 230 mph using downforce. In addition the shape of the underbody (an inverted wing) creates an area of low pressure between the bottom of the car and the racing surface. This sucks the car to road which results in higher cornering speeds.

The total aerodynamic package of the race car is emphasized now more than ever before. Teams that plan on staying competitive use track testing and wind tunnels to develop the most efficient aerodynamic design. The focus of their efforts is on the aerodynamic forces of negative lift or downforce and drag. The relationship between drag and downforce is especially important. Aerodynamic improvements in wings are directed at generating downforce on the race car with a minimum of drag. Downforce is necessary for maintaining speed through the corners. Unwanted drag which accompanies downforce will slow the car. The efficient design of a chassis is based on a downforce/drag compromise. In addition the specific race circuit will place a different demand on the aerodynamic setup of the car.

A road course with low speed corners, requires a car setup with a high downforce package. A high downforce package is necessary to maintain speeds in the corners and to reduce wear on the brakes. This setup includes large front and rear wings. The front wings have additional flaps which are adjustable. The rear wing is made up of three sections that maximize downforce.

The speedway setup looks much different. The front and rear wings are almost flat and are used as stabilizers. The major downforce is found in the shape of the body and underbody. Drag reduction is more critical on the speedway than on other circuits. Since the drag force is proportional to the square of the speed, minimizing drag is a primary concern in the speedway setup. Lap speeds can average over 228 mph and top speeds can exceed 240 mph on a speedway circuit. Effective use of downforce is especially pronounced in highspeed corners. A race car traveling at 200 mph. can generate downforce that is approximately twice its own weight.

Generating the necessary downforce is concentrated in three specific areas of the car. The ongoing challenge for team engineers is to fine tune the airflow around these areas.

Explanation:

plzz if it helps you then plzz mark me brainliest

Answer:

1. Point 2.

2. Either #1 or #4 (sorry, I'm not 100% sure).

3. I'm pretty sure #3.

I hope this helps!

Answer:

A atmospheric composition

Answer:

17.56 N

Explanation:

Given that,

Mass of a crate, m = 5 kg

It is on a 21.0° hill

We need to find the y component of the weight.

y component = mgsinθ

Put all the values,

y-component = 5×9.8×sin(21)

= 49×sin(21)

= 17.56 N

So, the y-component of the weight is 17.56 N.

Answer:

-45.745

Explanation:

it is negative because it is downwards.

The string vibrates the surrounding air, which produces a longitudinal wave.

Brainly if correct? Please and thank you :D

The guitar string vibrates the surrounding air, which produces a transverse wave.

A transverse wave can be used to represent the motion of a guitar string since it oscillates up and down perpendicular to its axis of motion.

Learn more about waves produced due to plucking a string of guitar here:

https://brainly.com/question/15853432?referrer=searchResults

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