A soccer player runs 80 yards down the field and then 30 yards back toward her
original starting point. This takes 55 seconds total. What is the average velocity of
the soccer player?
0.50 yd/s
0.91 yd/s
1.10 yd/s
2.00 yd/s

The complete question with the scale is missing, so i have attached it.

Answer:

930 g

Explanation:

The block surface is frictionless, therefore, the only force that can possibly be applied to the block from the hamster will be the normal force.

Now, the force of gravity on the hamster acts downward and equals mg. Hence, The normal component will be;

F_n = mgcosθ.

Now, if we Assume that the scale does not respond to horizontal force component, the downward component of the normal force will be expressed as;

F_d = F_n(cosθ)

The scale measures the downward component.

Earlier, we saw that; F_n = mgcosθ

Thus; F_d = mgcosθ × cosθ

F_d = mg(cos²θ)

Now, when the friction was high, the measurement of the scale was;

(m+ M)g

Where ;

m = mass of hamster

M = mass of block

Therefore, when the friction is removed the scale measurement is;

mgcos²θ + Mg or (mcos²θ + M)g

But this is in units of Newton's.

Thus;

Measurement in kg is;

(mcos²θ + M)

We are given;

m = 170 g = 0.17 kg

M = 830 g = 0.83 kg

From the attached scale image,

θ = 40°

Thus;

Measurement = (mcos²θ + M) = ((0.17 cos²40) + 0.83) = 0.93 kg or 930g

Answer:

Echolocation

- sound waves are being used and once they hit an object they are bounced back (that's how an echo is created)

- it's useful since it can tell you where something is

Answer:

Can dissolve

Explanation:

Answer:

Jack is 14, DiMarco is 12, Sam is 7

Explanation:

Answer:

The three ways thermal energy is transferred are;

1) Conduction

2) Convection

3) Radiation

Explanation:

1) The conduction of the heat from the open flame to the marshmallow is through the direct contact of the flame with the marshmallow, such that the flame the region of the combustion reaction, that produces light and heat touches the marshmallow

2) The convection process is the transfer of heat from the rising heated combustion products, as well as the heated air that rises from the flame

3) The radiation heat transfer is the transfer of the heat from the fire to the marshmallows directly by the heat the moves in the form of electromagnetic waves at temperatures above 1000 K, without the need for a medium, such that the marshmallow can be heated by the heat coming from side of the flame.

Answer:

0 N

Explanation:

Net force = mass × acceleration

∑F = ma

The velocity is constant, so the acceleration is 0.  Therefore, the net force is 0.

The net force acting on the bike is 0 N.

Net force is the sum of all forces acting on an object. The net force can be calculated using Newton's second law, which states that F = ma, where: F is the net force. m is the mass of the object. a is acceleration.

The velocity is constant, so the acceleration is 0.  Therefore, the net force is 0 N.

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Answer:

Explanation:

Given data

initital velocity u=15m/s

deceleration a=3m/s^2

time t= 4 seconds

final velocity v= ?

Applying the expression

v=u+at------1

substituting our data into the expression we have

v=15+3*4

v=15+12

v=27m/s

The velocity after 4 seconds is 27m/s

Answer:

i need the answer broo i am sooo koko

Explanation:

dsfedaes

Answer:

0.8 g/cm³

Explanation:

recall that the definition of density is the mass per unit volume of an object.

or mathematically:

density = mass / volume

here we are given that mass = 8 g and volume = 10 cm³

hence,

density = 8 g / 10cm³ = 0.8 g/cm³

The block has a mass of 8 g with a volume of 10 cm³. It density is mass divided by volume that is 0.8 g/cm³.

What is density?

Density of a substance is the measure of  its mass per unit volume. Density is dependent on some other factors beside mass and volume such as bond type, temperature and pressure.

The ratio of density of a substance to the density of water is called its specific gravity. If the substance is denser than water it will sink on water otherwise it will float on it.

The mass of the block of wood = 8 g

volume = 10 cm³

Density = mass / volume

              = 8 g/ 10 cm³

              = 0.8 g/ cm³

Therefore, the density of the wood block is 0.8 g/ cm³.

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Answer:

workdone = force x displacement

= 27.5 x 12.3

= 338.25 J

Answer:

If we compare 270 J and 2 380.5 J the higher is 2 380.5 J which is A 9 kg object traveling at 23 m/s

Explanation:

A 60 kg object traveling at 3 m/s

Given:

m = 60 kg

v = 3 m/s

Unknown:

KE or kinetic energy

Formula and solution:

KE = 1/2 mv²

KE = 1/2 (60kg) (3m/s)²

KE = (30kg) (9m²/s²)

Final Answer:

KE = 270 kg·m²/s² or simplify as 270 J

A 9 kg object traveling at 23 m/s

Given:

m = 9kg

v = 23m/s

Unknown:

KE or kinetic energy

Formula and solution:

KE = 1/2 mv²

KE = 1/2 (9kg) (23m/s)²

KE = (4.5kg) (529m²/s²)

Final Answer:

KE = 2 380.5 kg·m²/s² or simplify as 2 380.5 J

First answer is Muscle tissue. Second answer is Nervous tissue. Third answer is Epithelial tissue. And last answer is Connective tissue.

Answer:

B

Explanation:

One object speeds up before it slows to a stop.

When reading this type of graph, we know that when the points are far apart, then the object is definitely moving quickly. Also again, we know that when the points are besides each other, then we say that the object is moving slow. When the distance that is between the points are changed, the velocity of the object subsequently changes too, and therefore, we say that the object is accelerated. When there are lots of points in one location, we will see that the object is not moving.

This then translates into that

The object(s) at the top begins to slow, eventually, it increases in its speed, going forward, it slows down again, before it finally halts. The object at the bottom on the other hand, starts fast, before slowing down.

then:

"One object speeds up before it slows to a stop "

Answer:

v = 5.21 m/s

Explanation:

Let the initial speed be v.

The top of a building is 26.1 m above the ground level and the ball lands 112 m away from the base of the building.

We need to find the initial velocity of the ball.

Let it was at rest initially. Using the second equation of motion to find time of flight.

[tex]d=ut+\dfrac{1}{2}gt^2\\\\t=\sqrt{\dfrac{2d}{g}} \\\\t=\sqrt{\dfrac{2\times 26.1}{9.81}} \\\\t=2.3\ s[/tex]

No, using the formula of speed.

[tex]v=\dfrac{d}{t}\\\\v=\dfrac{12\ m}{2.3\ s}\\\\v=5.21\ m/s[/tex]

So, the initial velocity of the ball is 5.21 m/s.

Answer:

(a). The change in electric potential energy is 8.3 μJ.

(b).  The second particle moves away from the source charge.

Explanation:

Given that,

Charge of first particle = -8.8 nC

Charge of second particle = -4.3 nC

Distance = 0.11 m

They are released and the second particle moves 0.030 m,

(a). We need to calculate the change in electric potential energy

Using formula of potential energy

[tex]U=\dfrac{Kq_{1}q_{2}}{d}[/tex]

Change in potential energy

[tex]\Delta U=\dfrac{kq_{1}q_{2}}{d_{2}}-\dfrac{Kq_{1}q_{2}}{d_{1}}[/tex]

Put the value into the formula

[tex]U=\dfrac{9\times10^{9}\times(8.8\times10^{-9}\times4.3\times10^{-9})}{0.030}-\dfrac{9\times10^{9}\times(8.8\times10^{-9}\times4.3\times10^{-9})}{0.11}[/tex]

[tex]\Delta U=0.000008256\ J[/tex]

[tex]\Delta U=8.3\ \mu J[/tex]

(B). We need to find the second particle move toward or away from the source charge

We know that,

Both charges are same, so the second particle will be repul from the source charge.

So, The second particle moves away from the source charge.

Hence, (a). The change in electric potential energy is 8.3 μJ.

(b).  The second particle moves away from the source charge.

Answer:

1. 7

2. Mass

3. (b) Distance

4. (b) Force

5. (a) ML⁻¹T⁻²

6. (c) M⁻¹LT²

7. (c) M⁻¹L³T⁻²

8. (c) Pressure

9. (c) Young's modulus

10. (b) zero

11. (c) Infinite

12. (d) 1:4

13. (b) 0.6 J

14. (c) 45 N

15. (a) 0.4 cc

16. (a) 176.7 °F

17. (a) 10°C

18. (c) 50 K

19. b. H

Explanation:

15. Whereby the compressibility = 4 × 10⁻⁵ Pa⁻¹

The compression ratio for 100 Pa = 4 × 10⁻⁵ × 100 = 4 × 10⁻³

The Change for 100 cc = 4 × 10⁻³ × 100 cc = 0.4cc

Answer:

The correct choice is D. Its gravitational potential energy must increase

Explanation:

Conservation of Mechanical Energy

The total amount of mechanical energy, in a closed system in the absence of dissipative forces like friction or air resistance, remains constant.

This means that energy cannot disappear or appear and that potential energy can become kinetic energy or vice versa.

In a closed system like a pendulum, two types of energies are considered: Gravitational potential (U) and kinetic (K). Thus, the sum of both energies must remain constant in time.

Suppose the pendulum is at a state where U=150 J, and K=350 J. The total mechanical energy is:

M = 150 J + 350 J = 500 J

If the kinetic energy decreases to a new value, say K = 200 J, then the gravitational potential must increase to compensate for this new condition, that is: U = 300 J

The correct choice is D. Its gravitational potential energy must increase

Taking into account the definition of kinetic, potencial and mechanical energy, the correct answer is option D:  If  the pendulum's kinetic energy decreases Its gravitational potential energy must increase.

Kinetic energy is a form of energy. It is defined as the energy associated with bodies that are in motion and this energy depends on the mass and speed of the body.

Kinetic energy is defined as the amount of work necessary to accelerate a body of a given mass and at rest, until it reaches a given speed. Once this point is reached, the amount of accumulated kinetic energy will remain the same unless there is a change in speed or the body returns to its state of rest by applying a force.

On the other hand, potential energy is the energy that measures the ability of a system to perform work based on its position. In other words, this is the energy that a body has at a certain height above the ground.

Gravitational potential energy is the energy associated with the gravitational force. This will depend on the relative height of an object to some reference point, the mass, and the force of gravity.

Finally, mechanical energy is that which a body or a system obtains as a result of the speed of its movement or its specific position, and which is capable of producing mechanical work. Then:

Potential energy + kinetic energy = total mechanical energy

The principle of conservation of mechanical energy indicates that the mechanical energy of a body remains constant when all the forces acting on it are conservative (a force is conservative when the work it does on a body depends only on the initial and final points and not the path taken to get from one to the other.)

Therefore, if the potential energy decreases, the kinetic energy will increase. In the same way, if the kinetics decreases, the potential energy will increase.

This principle can be applied in this case. The mechanical energy of the pendulum remains constant when all the forces acting on it are conservative.

So, the correct answer is option D:  If  the pendulum's kinetic energy decreases Its gravitational potential energy must increase.

Learn more about mechanical energy:

Answer:

using the pressure of stump

Answer: Using the pressure of a stump

Answer:

1) Skis have a large area to reduce the pressure on the snow. This ensures that the skis do not sink into the snow too far.

2) The pressure under the studs on the soles of football shoes is high enough for them to sink into the ground, which gives extra grip.

3) A vacuum cleaner has a fan inside that creates a low pressure inside the device. Consequently, air and dirt particles are sucked into the device.

Answer:

Energy is found only in moving objects : False

Energy is never created : True

Energy can move matter : True

Energy is the same as force : False

Energy is never destroyed : True

Explanation:

Plato

Energy can neither be created nor be destroyed. Energy is generated by both moving and stationary objects but in different forms. Energy can move matter. Hence, options 2, 3 and 5 are correct.

According to the law of conservation of energy, energy can neither be created nor be destroyed. However, it can be transformed from one state to the other. For example electrical energy can be converted to light energy.

Energy is generated in both stationary and moving object. The energy for a particle gained by its motion is called its kinetic energy. The energy stored on an object at rest is called potential energy.

Energy can move matter as well. The energy used to displace an object is called work done on the object. The unit of energy and work done  is joule. Therefore, options 2, 3 and 5 are correct.

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Answer:

128

Explanation:

One clomiter is 1.06 multipled by 80