a car travelling at 20 ms-1 accelerates uniformly for 8 s until its velocity reaches 36 ms-1.what are the acceleration and the average velocity of the car during this period​

Answer:

Friction is what holds your shoe to the ground. The friction present on the ice is very little, this is the reason why it is hard to walk on the slippery surface of the ice.

Explanation:

Answer:

A bullet fired simultaneously from the same height

Explanation:

It will reach the ground first because a greater force is being acted upon it. The first option is only acted on by gravity

Answer:

The value is  [tex]M = 42.3 \ kg[/tex]

Explanation:

From the question we are told that

    The first  position of the fulcrum  is  x = 49.7 cm

    The mass  attached is [tex]m = 41.5 \ g[/tex]

    The position of the attachment is  [tex]x_1 = 28.5 \ cm[/tex]  

    The second position of the fulcrum is  [tex]x_2 = 39.2 \ cm[/tex]

Generally the sum of clockwise torque =  sum of anti - clockwise torque

So  

       [tex]CWT = m (x_2 - x_1)[/tex]

Here CWT  stands for clockwise torque

       [tex]ACWT = M ( x - x_2)[/tex]

So

      [tex]m (x_2 - x_1) = M ( x - x_2)[/tex]

=>   [tex]41.5 (39.2 - 28.5 ) = M ( 49.7 -39.2 )[/tex]

=>    [tex]M = 42.3 \ kg[/tex]

Answer:

The earths magnetic field

Explanation:

Answer:

Gravity

Explanation:

its an invisible force that pulls objects

toward each other.

hope it helps

Answer:

False

Explanation:

They had no free oxygen though they has oceans forming and it was very hot and today is much different hope that helps!

Answer:

a. Since h = 5.74 m > 5.7 m, the height of the cliff, the block of ice will successfully launch to the top of the cliff.

b. -2.81 m/s²

c. 3.78 s

d. -351.25 N

Explanation:

a. After landing on the flat land above, each block of ice travels 20 meters while slowing to a stop.

For the block of ice to reach the top of the cliff, its maximum height, h should be greater than or equal to 5.7 m. That is, h ≥ 5.7 m.

The maximum height of a projection h, projected with an initial velocity v at an angle Ф is h = v²sin²Ф/2g where g = acceleration due to gravity = 9.8 m/s².

For the block of ice, v = 15 m/s and Ф = 45°. So,

h = v²sin²Ф/2g

= (15 m/s)²sin²45/(2 × 9.8 m/s²)

= 225 (m/s)²(1/√2)²/19.6 m/s²

= 225 (m/s)²(1/2)/19.6 m/s²

= 112.5 (m/s)²/19.6 m/s²

= 5.74 m

Since h = 5.74 m > 5.7 m, the height of the cliff, the block of ice will successfully launch to the top of the cliff.

The graph is in the attachment.

b. What is the rate of acceleration while the blocks slow to a stop?

Using v² = u² + 2as where u = initial horizontal velocity of block = 15m/scos45° = 10.61 m/s, v = final velocity of block = 0 m/s since it stops, a = acceleration and s = distance block moves = 20 m

So, a =  (v² - u²)/2s

substituting the variables into the equation, we have

a =  ((0 m/s)² - (10.61 m/s)²)/2(20 m)

= - 112.57 (m/s)²)/40 m

= -2.81 m/s²

c. How long do the blocks take to slow to a stop?

Using v = u + at where u = initial horizontal velocity of block = 10.61 m/s v = final velocity of block = 0 m/s since it stops, a = acceleration = -2.81 m/s² and t = time it takes block of ice to stop

So, making t subject of the formula,

t = (v - u)/a

substituting the values of the variables, we have

t = ( 0 m/s - 10.61 m/s)/-2.81 m/s²

= -10.61 m/s/-2.81 m/s²

= 3.78 s

d.  What is the amount of friction between the ice and the snowy ground?

The frictional force, f = net force on block of ice

f = ma where  m = mass of bock = 125 kg and a = acceleration of block = -2.81 m/s²

f = ma

= 125 kg(2.81 m/s²)

= -351.25 N

Answer:

D.

Explanation:

A compound containing metallic bonds

hope it helps!

Answer:

1.1 lbs

Explanation:

To convert kg to lbs you multiply kilograms by 2.2. So 0.5kg × 2.2 equals to 1.1 lbs

Answer:

Possibly shape.

Explanation:

Because it is ripped in half. As you guys and the questioner can see that there is a wiggly strip down the middle. That also cause of a shape change.

I really hope my answer is right ^_^  

The characteristic of matter which is undergoing change in the picture is it's shape as it is being teared apart.

Matter in chemistry, is defined as any kind of substance that has mass and occupies space that means it has volume .Matter is composed up of atoms which may or not be of same type.

Atoms are further made up of sub atomic particles which are the protons ,neutrons and the electrons .The matter can exist in various states such as solids, liquids and gases depending on the conditions of temperature and pressure.

The states of matter are inter convertible into each other by changing the parameters of temperature and pressure.Matter possesses both particle and wave characteristics.Phase is a form of matter having uniform composition as well as physical properties.

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Answer:

P = 33.6 [N]

Explanation:

To solve this problem we must use Newton's second law, which tells us that the sum of forces on a body is equal to the product of mass by acceleration.

∑F = m*a

where:

F = forces [N]

m = mass = 14 [kg]

a = acceleration = 6 [m/s²]

[tex]F = 14*6\\F = 84 [N][/tex]

In the second part of this problem we must find the work done, where the work in physics is known as the product of force by distance, it is important to make it clear that force must be applied in the direction of movement.

[tex]W = F*d[/tex]

where:

W = work [J]

F = force = 84 [N]

d = displaciment = 40 [m]

[tex]W = 84*40\\W = 3360 [J][/tex]

Finally, the power can be calculated by the relationship between the work performed in a given time interval.

[tex]P=W/t\\[/tex]

where:

P = power [W]

W = work = 3360 [J]

t = time = 100 [s]

Now replacing:

[tex]P=3360/100\\P=33.6[W][/tex]

The power is given in watts

Answer:

Vba = -20 m/s - 25 m/s = -45 m/s

Vab = 25 m/s + 20 m/s = 45 m/s

Explanation:

Relative Velocity

The relative velocity of object B with respect to object A (Vba) measures the velocity of B in the rest frame of object A.

It's calculated as:

Vba = Vb - Va

The velocity of car B is Vb=-20 m/s and the velocity of car A is Va=90 Km/h.

Converting Va to m/s:

Va = 90 Km/h * 1000/3600 = 25 m/s

Thus, the relative velocity of B with respect to A is:

Vba = -20 m/s - 25 m/s = -45 m/s

And the relative velocity of A with respect to B is:

Vab = 25 m/s + 20 m/s = 45 m/s

Answer:

Explanation:

The time taken can be found by using the formula

[tex] t = \frac{d}{v} \\ [/tex]

d is the distance

v is the velocity

From the question we have

[tex]t = \frac{3.5}{4.8} \\ = 0.72916...[/tex]

We have the final answer as

Hope this helps you

Answer:

The answer is C) II and III only

Explanation:

Answer: They are put in front for defense so so they can block the opponents from getting the ball

Explanation:

Answer:

Heavier football players are usually on the front line because they have a low point in gravity therefore they are able to block the back running players in a better way. And its Newton's second law.

Explanation:

Answer:

It is always constant unlike weight

Explanation:

distance=16km=16000m

time=0.25hours=1/4hr=15min=900sec

speed=dist./time

=16000/900=160/9=17.777m/s

speed=17.78m/s (rounded)

Answer:

64

Explanation:

Avg. speed = total distance/total time

Avg. speed= 16km/0.25h

Avg. speed= 64km/h

Answer:

B

Explanation:

Answer:

If you take A0 to be the initial sample of iodine-131, you will be left with. 12⋅A0=A02→ ... m24 hours=12.5%mo=12.5⋅10−2⋅mo

Explanation:

is that what u look for

Sample I-131 decays to 12.5% in 24.21 days.

Half-life, in radioactivity, is the amount of time needed for half of a radioactive sample's atomic nuclei to decay (change spontaneously into other nuclear species by emitting particles and energy), or, alternatively, the amount of time needed for a radioactive material's rate of disintegrations per second to decrease by half.

Give parameters:

Half-life of  the radioactive element I-131:T = 8.07 day

It decays to 12.5% means it decays to 1/8.

According to definition of half-life,

The radioactive element I-131 decays to half in 8.07 days.

So, the radioactive element I-131 decays to 1/8 in 3×8.07 days = 24.21 days.

Hence,  the radioactive element I-131 decays to12.5% in 24.21 days.

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Explanation:

1.Seeds have endosperm which provides nourishment for a new plant, but spores do not have any stored food supplies.

hope it helpful

Answer:

B. 1200

Explanation:

60 sec in one min in 2 min there will be 120 sec. 10x120=1200

Answer:

Explanation:

The momentum of an object can be found by using the formula

momentum = mass × velocity

From the question we have

momentum = 0.15 × 35

We have the final answer as

Hope this helps you

Answer:

8.5m/s

Explanation:

Using the equation of motion

v² = u² + 2gH

v is the final speed of the diver

u  is the initial speed of the diver

g is the acceleration due to gravity

H is the height of the object

Given the following

V = 1.3m/s

H = 3.60m

g = 9.8m/s²

Required

Initial speed of the diver u

Substitute the given values into the formula:

v² = u² -2gH

1.3² = u²  - 2(9.8)(3.60)

1.69 = u²-70.56

u² = 1.69+70.56

u² = 72.25

u = √72.25

u = 8.5m/s

Hence the diver's speed, in m/s, just before she enters the water is 8.5m/s

Answer:

The effects of the Moon's rotation includes;

1) The Moon rotation and revolution gives the appearance of a perfectly still Moon to observers of the Moon from the Earth

2) The Moon has two sides, the near side that continuously faces the Earth and the "back" or far side, which is also known as the dark side of the Moon

The effect of the Moon's revolution

1) The tides in the ocean and water bodies, due to the gravitational forces from the Moon

2) The changes in the observed shape of the Moon due to the amount of Sunlight that is able to be reflected from the Moon as a result of the relative position of the Moon, the Earth and the Sun, at a given point in time

3) Lunar and Solar eclipse, when the Earth and the Moon blocks the light coming from the Sun respectively, due to their combined revolution

Explanation:

The duration of the Moon's orbit round the Earth = 27.322 days

The time it takes the Moon to rotate round its axis = 27 days

The Moon is the closest cosmic body to the Earth.

If a cell is placed in a hypertonic solution, water will leave the cell, and the cell will shrink. In an isotonic environment, there is no net water movement, so there is no change in the size of the cell. When a cell is placed in a hypotonic environment, water will enter the cell, and the cell will swell.

Answer:

C

Explanation:

I figured it sounded more accurate

Answer:

30 Watts

Explanation:

 Power = Work/Time

Work = Force*Distance

Power = Force * Distance / Time

Power = 15 N * 20 meters / 10 sec

Power = 30 Watts

Answer:

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 50 × 0.6

We have the final answer as

Hope this helps you

Answer:

The value is  [tex]u = 27.93 \ m/s[/tex]

Explanation:

From the question we are told that

   The  mass of the ball is [tex]m = 0.250 \ kg[/tex]

    The radius of the circle is  [tex]r = 0.5 \ m[/tex]

    The force exerted is  [tex]F = 33 \ N[/tex]

    The  speed of the ball on top of the circle is  [tex]v = 13.0 \ m/s[/tex]

Gnerally from the law of energy conservation we have that

     [tex]PE + W = \Delta KE[/tex]

Here PE  is the potential energy of the pitcher which is mathematically represented as

      [tex]PE = m * g * (2 r )[/tex]

=>   [tex]PE = 0.250 * 9.8 * (2 * 0.5 )[/tex]  

=>   [tex]PE = 24.5\ J[/tex]

And  W  is the workdone by the force applied which is mathematically represented as

       [tex]W = F * \pi * r[/tex]

=>    [tex]W = 33 * 3.142 * 0.5[/tex]

=>    [tex]W = 51.84 \ J[/tex]

And   [tex]\Delta KE[/tex] is the change in kinetic energy which is mathematically represented as

       [tex]\Delta KE = \frac{1}{2} * m * (v^2 - u^2 )[/tex]

=>    [tex]\Delta KE = \frac{1}{2} * 0.250 * ( 13^2 - u^2 )[/tex]

=>    [tex]\Delta KE = 0.125 * ( 13^2 - u^2 )[/tex]

=>    [tex]\Delta KE = 21.125 - 0.125u^2[/tex]

So

      [tex]24.5 + 51.84 = 21.125 - 0.125u^2[/tex]

=>    [tex]u = 27.93 \ m/s[/tex]

The velocity of the ball released at the bottom is required.

The velocity of the ball released at the bottom is 24.56 m/s

F = Force = 33 N

r = Radius of loop = 0.5 m

m = Mass of ball = 0.25 kg

u = Initial velocity of ball = 13 m/s

v = Final velocity

g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]

The energy balance of the system is given by

[tex]F\pi r+mg2r=\dfrac{1}{2}m(v^2-u^2)\\\Rightarrow v=\sqrt{\dfrac{2}{m}(F\pi r+mg2r)+u^2}\\\Rightarrow v=\sqrt{\dfrac{2}{0.25}(33\times \pi\times 0.5+0.25\times 9.81\times 2\times 0.5)+13^2}\\\Rightarrow v=24.56\ \text{m/s}[/tex]

The velocity of the ball released at the bottom is 24.56 m/s.

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