The number of significant figures in the measurement 0.000 305 kg is

six.

two.

seven.

three.

The density of the concrete is approximately 0.965 g/cm³. The result does not support the statement that rebar is mostly iron.

The density of a substance can be calculated by dividing its mass by its volume. In this case, the mass of the concrete is 43.8 grams and the volume is calculated by multiplying the length, width, and height, which is 3.7 cm x 2.1 cm x 5.8 cm = 45.4014 cm³ (rounded to the nearest 0.0001 cm³). Therefore, the density of the concrete is 43.8 g / 45.4014 cm³ ≈ 0.965 g/cm³.

(b) Since the density of the concrete in (a) is less than the density of iron (approximately 7.87 g/cm³), the result does not support the statement that rebar is mostly iron.

Explanation:

Traffic jams on boat ramps can be avoided if everyone follows and practices some common courtesy at the ramp. While retrieving the boat from the water surface, it is a common courtesy to place the boat into the launch area only after the towing vehicle has arrived at the ramp. Drop off the driver and then generously wait wait offshore for your turn. Try to clear up the ramp until the trailer arrives at the ramp. This is a most common practice that every body should follow as a common courtesy to others.

If your inboard or outboard boat runs aground, after shifting the weight away from the point of impact, you should stop the engine and lift the outdrive.

A gasoline engine can be defined as a mechanical system that is primarily designed and developed to only make use of hydrocarbons (organic compounds) such as fuels, in order to enable a vehicle or boat to move from one point to another on a water body.

Generally, an outboard gasoline engine is installed on the outside of a vehicle or a boat while an inboard gasoline engine is typically installed on its inside.

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Answer:

The best answer to the question: If there is no crosswalk or limit line near an intersection, you should stop _____, would be, C: at the corner.

Explanation:

This regulation is part of what is taught to drivers before they get their drivers license. In essence, the regulation says that if you come to an intersection, and there is a limit line, or a crosswalk, of course you know you must stop before moving on. The problem comes when neither a crosswalk, nor a limit lines is marked near the intersection. To solve this, the regulation states that even if there are no such limiting lines, or marks, the driver must still come to a stop at the corner, before entering the intersection. This is why the anwer is C.

Water currents have the most significant effect on smaller and lighter boats such as kayaks, canoes, and dinghies as these boats have less weight and hence lower inertia, making them less capable of resisting the force of the water current. However, all types of boats, including large vessels, are affected by water currents.

The water current can have a great impact on different types of boats but it especially affects smaller and lighter boats like kayaks, canoes, or dinghies, which are more susceptible to being moved by currents. This is due to these boats having less weight and hence lower inertia/displacement, which means they are less capable of resisting the force of the current.

This does not mean that larger boats are not affected by water currents. Even large vessels such as cargo ships are impacted by currents. They must account for the current when navigating, and miscalculations can lead to off-course journeys and even accidents. However, changes in their courses brought about by currents are less abrupt compared to smaller boats.

The effect of water current on a boat also depends on other factors like the skill and experience of the boat operator, the boat's design, and the conditions of the water body.

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Answer:

Applied force, weight, normal force and frictional force

Explanation:

Bob is pushing a lawn mower up a hill with the mower tilting slightly to the right. We have to write the forces acting on the mower.

The following are the forces that are acting on the mower.

1. Applied force - The force with which Bob is pushing a lawn.

2. Weight - Its weight is equal to, W = m g

3. Normal force - that balances its weight

4. Frictional force - It always opposes the motion of the mower.

Hence, this is the required solution.

The lawn mower is acted upon by four different forces.

Vector quantities are those quantities that posses both magnitude and direction. Force is a vector quantity. Hence, the resultant force acting on a lawn mover can be obtained as the resultant of the four forces that act on the mower.

The four forces that act on the lawn mower are;

Hence, the lawn mower is acted upon by four different forces.

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Answer:

B. Certified

Explanation: I agree with the other person and i also believe it is correct

Using the wave equation, the frequency of the sound wave produced by the guitar string can be calculated by dividing the velocity (10.5 m/s) by the wavelength (0.15 m), resulting in a frequency of 70 Hz.

The student is asking about the frequency of a sound wave produced by a plucked guitar string. To calculate this, we can use the basic wave equation v = f λ, where v is the velocity of the wave, f is the frequency, and  λ is the wavelength. Given the wavelengths of 0.15 m and the velocity of 10.5 m/s, we can rearrange the formula to solve for the frequency (f):

f = v / λ

f = 10.5 m/s / 0.15 m

By calculating this, we find that the frequency of the wave is 70 Hz.

Answer:

A. 468 Hz while approaching, 440 Hz through the crossing, 415 Hz while receding

Explanation:

When bus is approaching the stand where boy is standing then the frequency is given as

now we know that

[tex]f_0 = 440 Hz[/tex]

[tex]v = 330 m/s[/tex]

[tex]v_b = 20 m/s[/tex]

frequency is given by

[tex]f_1 = f_0 \frac{v}{v - v_b}[/tex]

now plug in the data in the equation

[tex]f_1 = 440 \times \frac{330}{330 - 20}[/tex]

[tex]f_1 = 468 Hz[/tex]

Now when bus is moving away from the bus stop then frequency is given as

[tex]f_2 = f_0 \frac{v}{v + v_b}[/tex]

[tex]f_2 = 440 \times \frac{330}{330 + 20}[/tex]

[tex]f_2 = 415 Hz[/tex]

so here correct answer would be

A. 468 Hz while approaching, 440 Hz through the crossing, 415 Hz while receding

North and south poles attract each other.

The relationship between velocity (v), wavelength (w) and frequency (f) is expressed as:

v = w f

Plugging in the given values into the equation:

v = 0.643 m (3.25 e 10 Hz)

Where Hz = 1 / s , therefore:

v = 0.643 m (3.25 e 10 / s)

v = 2.09 e 10 m / s

Taking into account the definition of wavelength, frecuency and propagation speed, the velocity of waves having wavelength 0.643 m and frequency 3.25 e 10 Hz is 2.09 e 10 m/s.

Wavelength is the minimum distance between two successive points on the wave that are in the same state of vibration. It is expressed in units of length (m).

On the other side, frequency is the number of vibrations that occur in a unit of time. Its unit is s⁻¹ or hertz (Hz).

Finally, the propagation speed is the speed with which the wave propagates in the medium, that is, it is the magnitude that measures the speed at which the wave disturbance propagates along its displacement.

The propagation speed relate the wavelength (λ) and the frequency (f) inversely proportional using the following equation: v = f×λ

In this case, you know:

Replacing in the definition of propagation speed:

v= 3.25 e 10 Hz×  0.643 m

Solving:

v= 2.09 e 10 m/s

Finally, the velocity of waves having wavelength 0.643 m and frequency 3.25 e 10 Hz is 2.09 e 10 m/s.

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Answer:

In a collision, the SECOND collision is when an unsecured driver strikes the inside of the vehicle.

Explanation:

When driver in the car is unsecured then it means that the driver is not having his safety seat belt.

Now when collision occurs between the car and some other object then due to the property of inertia of driver it has tendency to move in the direction of his motion.

So the driver will continue his motion and collide with other parts of the car and due to this he may got injured.

So in any car collision there are two types of collision

first is the collision of car with other objects

second collision is between car and the driver inside the car

Answer:

Orbital

Explanation:

Quantum theory established that electrons doesn't follow a perfectly determined pathway in their movement around the nucleus. Rather, this theory establishes a region, called orbitals, where an electron is likely to be found in an atom.

Answer:

its b on oddessey ware

Explanation:

Final answer:

The final velocity of marble B after the collision is determined by using the conservation of momentum, which yields a resulting velocity of 1.8 m/s.

Explanation:

To solve the problem, we use the principle of conservation of momentum because no external forces are acting on the system of the two marbles. The total momentum before the collision must equal the total momentum after the collision. The equation for this is:

m1 * v1_initial + m2 * v2_initial = m1 * v1_final + m2 * v2_final

where:

m1 = Mass of Marble A = 0.06 kg

m2 = Mass of Marble B = 0.03 kg

v1_initial = Initial velocity of Marble A = 0.7 m/s

v2_initial = Initial velocity of Marble B = 0 m/s (since it is at rest)

v1_final = Final velocity of Marble A after collision = -0.2 m/s

v2_final = Final velocity of Marble B after collision (this is what we are solving for)

Plug in the known values and solve for v2_final:

0.06 kg * 0.7 m/s + 0.03 kg * 0 m/s = 0.06 kg * (-0.2 m/s) + 0.03 kg * v2_final

0.042 kg∙m/s = -0.012 kg∙m/s + 0.03 kg * v2_final

Add 0.012 kg∙m/s to both sides:

0.054 kg∙m/s = 0.03 kg * v2_final

Divide both sides by 0.03 kg to get the final velocity of Marble B:

v2_final = 0.054 kg∙m/s / 0.03 kg = 1.8 m/s

Therefore, the resulting velocity of marble B after the collision is 1.8 m/s.

Final answer:

You lurch forward in a bus that suddenly slows due to Newton's First Law of Motion, or the law of inertia, which suggests an object in motion stays in motion unless acted on by an unbalanced force. When the bus accelerates, inertia causes you to feel pushed back as your body prefers to remain at rest. Understanding this law helps in recognizing the importance of safety measures like seatbelts.

Explanation:

Understanding Movement in a Bus: Newton's First Law of Motion

When a bus suddenly slows down, you lurch forward because of Newton's First Law of Motion, also known as the law of inertia. This law states that an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. Since your body wants to keep moving at the same speed the bus was going before it slowed down, you lurch forward when the bus decelerates.

Similarly, when the bus speeds up, you might feel like you are being pushed back into your seat. This is again due to the law of inertia. Your body wants to remain at its state of rest (or moving at a constant speed if the bus was already moving), so when the bus accelerates, it creates a temporary imbalance, making you feel pushed back.

Using seatbelts or holding onto something stable inside the bus can counteract these effects by providing the necessary force to keep you in place, thereby preventing injury and ensuring safety.

Why Understanding Newton's First Law is Important

The applications of Newton's First Law are seen in everyday life, not just in theoretical physics. It explains a wide range of phenomena, from why it's crucial to wear a seatbelt to the importance of headrests in preventing whiplash injuries. Understanding these principles can help improve personal safety and awareness in moving vehicles.

When merging onto an expressway from an acceleration lane, you should gradually accelerate to match the speed of traffic and merge safely. Avoid excessive speed, travel during less congested times, and decelerate gradually to avoid abrupt stops.

When merging onto an expressway from an acceleration lane, you should achieve a speed close to that of the traffic on the expressway. It's important to use the acceleration lane to increase your speed to a safe level that allows you to merge into traffic without causing other drivers to brake abruptly. To ensure safety, remember to avoid high speed driving beyond the flow of traffic, travel when congestion is light to reduce the need to merge at very high speeds, and avoid unnecessary braking by smoothly accelerating up to highway speeds and planning for potential traffic conditions that allow for gradual deceleration before stops.

Observing the other drivers on the road will also help. Drivers going in the same direction as you appear to move at lower speeds — this is relative motion. However, ensure you're paying attention to your speedometer to maintain an appropriate speed. Oncoming traffic may seem to be moving much faster due to their relative speed in comparison to your vehicle, but do not let this perception cause you to speed up excessively when merging.

Answer: C. Coal power can be generated both day and night.

Explanation:

Coal is an important form of source of energy. It is a non-renewable source of energy. It is obtain by mining of the surface below the earth crust.  Coal plays an important role in generation of electricity worldwide.  

It acts as a raw material for the generation of electricity in both day and night. When the coal is turned into a gas. The gas turbine is hot enough to boil the water that can be used to make the steam. The steam spin another type of turbine so as to generate the electricity.

Answer:

16.110 g

Explanation: