A driver sets out on a journey. for the first half of the distance she drives at the leisurely pace of 30 mi/h; during the second half she drives 60 mi/h, the driver's average speed on this trip is 40 mi/h.
To find the average speed for the entire trip, we can use the formula for average speed:
Average Speed = Total Distance ÷ Total Time.
In this case, the driver covers the first half of the distance at 30 mi/h and the second half at 60 mi/h.
Let's assume the total distance of the trip is [tex]\(D\)[/tex] miles. The first half of the distance is [tex]\(D/2\)[/tex] miles, and the second half of the distance is also [tex]\(D/2\)[/tex] miles.
Let's calculate the time taken for each half of the distance:
Time taken for the first half = Distance / Speed
= [tex]\((D/2) \, \text{miles} / (30 \, \text{mi/h})\)[/tex].
Time taken for the second half = Distance / Speed
= [tex]\((D/2) \, \text{miles} / (60 \, \text{mi/h})\).[/tex]
Total time for the trip = Time for the first half + Time for the second half.
Total time = [tex]\((D/2) / (30) + (D/2) / (60)\)[/tex].
Total time = [tex]\(\dfrac{D}{60} + \dfrac{D}{120}\)[/tex].
Total time = [tex]\(\dfrac{3D}{120} = \dfrac{D}{40}\)[/tex].
Now we can calculate the average speed:
Average Speed = Total Distance / Total Time.
Average Speed = [tex]\(D / \dfrac{D}{40}\)[/tex].
Average Speed = [tex]\(40\) mi/h[/tex].
Thus, the driver's average speed on this trip is 40 mi/h.
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The driver's average speed on this trip is 30 mi/h.
Explanation:To find the average speed on this trip, we can use the formula: average speed = total distance / total time. Let's assume the total distance is D miles. According to the given information, the driver spends the first half of the distance at a speed of 30 mi/h and the second half at a speed of 60 mi/h. Therefore, the total time taken for the trip is D / (30 mi/h) + D / (60 mi/h) = D / (1/30 h) + D / (1/60 h) = 2D / (1/60 h) = 120D h. We can substitute this value into the average speed formula and simplify: average speed = D / (120D h) = 1/120 h. So, the driver's average speed on this trip is 1/120 h = 0.00833 h = 0.00833 x 60 min = 0.5 min/h = 0.5 x 60 = 30 mi/h. Therefore, the driver's average speed on this trip is 30 mi/h.
How does a ray of light traveling parallel to the principal axis of a concave mirror be reflected back?
Answer:
Light ray will bend inwards and pass through the focus on principle axis after reflection
Explanation:
As we know that for curved mirror the equation is given as
[tex]\frac{1}{d_i} + \frac{1}{d_0} = \frac{1}{f}[/tex]
now here we know that initially light is travelling parallel to principle axis for given concave mirror.
So here the object position must be at very large distance from the mirror
[tex]d_0[/tex] = infinite
so here by above equation we will have
[tex]\frac{1}{d_i} + \frac{1}{infinite} = \frac{1}{f}[/tex]
now from this equation we can say
[tex]d_i = f[/tex]
so position of image will be at focus of mirror which means the parallel light will pass through focus after reflection from mirror.
You are waiting to turn left into a small parking lot. a car approaching from the opposite direction has a turn signal on. you should _______________.
a. wait until the other car starts its turn before making your turn
b. make your turn if the driver is signaling for a left turn
c. make your turn if the driver is signaling for a right turn
When waiting to turn left and a car is approaching from the opposite direction with a turn signal, you should wait until the other car starts its turn before making yours (a). This applies regardless of whether they signal a left or right turn.
Explanation:In the situation where you are waiting to turn left into a small parking lot and a car is approaching from the opposite direction with a turn signal on, you need to exercise caution. It's important to note that you should wait until the other car starts its turn (a) before making your turn. This is applicable whether the driver is signaling for a left turn or a right turn. You should never make assumptions based on signal indicators as drivers might sometimes forget to turn them off or mistakenly leave them on.
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The rare earth elements include
how much energy is released if a sample loses 0.0001 kg mass through radioactive decay
9x10^13 J is the energy released if a sample loses 0.0001 kg mass through radioactive decay.
What is radioactive decay give an example?As in step with the quantum theory, it isn't always feasible to predict whether a given atom will undergo radioactive decay or nuclear disintegration. Not unusual examples of radioactive decay consist of alpha decay, proton emission, double proton emission, beta decay, electron capture, and neutron emission.
Radioactive decay is the system via which a volatile atomic nucleus loses electricity by radiation. A material containing unstable nuclei is considered radioactive. Three of the most common kinds of decay are alpha decay, beta decay, and gamma decay, all of which contain emitting one or greater debris.
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Why does the oil in some salad dressings rise to the top of the bottle?
The net force on a car is zero in both the horizontal and vertical directions. Which two situations could be true about the motion of the car?
1.The car is speeding up onto the highway.
2.The car is parked.
3.The car is moving at a fixed speed and direction.
4.The car is braking (slowing down).
5.The car is being struck by another car.
Answer:
Option 2 and 3
Explanation:
When the net force on the car is zero, the acceleration is also zero.
Along horizontal direction, the net force is zero. It means the car is moving with fixed speed and same direction.
Along vertical direction, the weight of the car is balanced by the normal reaction.
When the car is parked, the weight of the car is balanced by the normal reaction.
You are standing on a skateboard, initially at rest. a friend throws a very heavy ball towards you. you can either catch the object or deflect the object back toward your friend (such that it moves away from you with the same speed as it was originally thrown). what should you do in order to maximize your speed on the skateboard?
You should deflect the
ball in order to maximize your speed on the skateboard.
Since this creates a larger impulse, you want to deflect the ball. Splitting it
up into catching and throwing the ball may by something you can think of deflecting
the ball. First, you need to catch the ball, which in turn would push you
forward with some speed. (The speed we are talking about should obviously be
equal to option A, where you catch the ball). Now, throw the ball back to him
since these two processes are equal to deflecting the ball. Throwing a mass away
from you would cause or enable you to move even fast.
When starting a foot race, a 70.0-kg sprinter exerts an average force of 650 n backward on the ground for 0.800 s. what is his final speed?
The sprinter's final speed is calculated using Newton's second law and kinematic equations, resulting in a final speed of 7.43 m/s based on the provided force exerted and the time duration.
Explanation:The question involves calculating the final speed and distance traveled by a sprinter, which is a physics concept involving Newton's second law of motion and the basic principles of kinematics. To find the sprinter's final speed, we use the relationship derived from Newton's laws that connects force, mass, acceleration, and velocity. Given that the sprinter exerts an average force of 650 N backward on the ground for 0.800 s, and has a mass of 70.0 kg, we can calculate the acceleration and then use it to find the final speed.
First, we calculate the acceleration using Newton's second law, F = ma. The force exerted on the ground is equal and opposite to the force exerted on the sprinter (Newton's third law), so:
Acceleration, a = F/m = 650 N / 70.0 kg = 9.29 m/s2
Then, we use the equation of motion, v = u + at, where u is the initial velocity (0 m/s, as the sprinter starts from rest), a is the acceleration, and t is the time. Substituting the values, we get the final speed:
Final speed, v = 0 + (9.29 m/s2 × 0.800 s) = 7.43 m/s
if 2 joules of work is done in raising an apple 8 meters, how much force was exerted?
Which characteristic is not a characteristic of plastic?
1.easy to mold
2.good conductor of heat
3.lightweight and durable
4.repels water
. A pencil (m = 10 g) and eraser (m = 20 g) are placed 2.5 cm apart. If they are left on a surface without friction they will eventually come into contact with one another. Assuming that the pencil is the object to move, how long (in hours) will it take the two objects to touch?
Which has the greater momentum when moving?
Momentum is found by multiplying an object's mass by its velocity. While velocity influences momentum, mass plays a significant role, hence a player's momentum is much larger than a football's, despite having less velocity. Comparatively, an elephant could have more momentum than a cheetah, depending on their respective masses and velocities.
Explanation:Momentum is a crucial concept in physics, and it is calculated as the product of an object's velocity and mass (momentum = mass x velocity). So, the momentum changes when either mass or velocity alters. When comparing the velocity of a ball and a player, even though the ball may have greater velocity, the player, having much more mass, thus has a significantly larger momentum. The player's momentum is about 86 times greater than the football's. As such, the player's motion is only slightly affected when the ball is caught, due to their greater momentum.
In another example, to determine which has a larger magnitude of momentum; a 3000-kg elephant moving at 40 km/h or a 60-kg cheetah moving at 112 km/h, we would need to calculate the momentum for both and compare. An object's mass and velocity both play an integral role in determining its momentum.
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While refrigerant 410a is a near azeotropic refrigerant, it is still best when charging to remove the r-410a as a _______ from the storage cylinder?
A piece of metal weighs 300 n in air and 232.5 n when submerged in water. find the density of the metal.
1.) A red opaque object is ...?
(A.)absorbs all colors of the visible spectrum equally
(.B.) absorbs red light only.(C. )reflects all colors of the visible spectrum but red.(D.) reflects red light only.
Any red opaque object reflects red light only.
What is opaque object?An opaque object is such that no light is able to pass through it.
Given is a red opaque object.
Red opaque object reflects red light only.
Therefore, any red opaque object reflects red light only.
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Making data appear as if it is coming from somewhere other than its original source is known as what
Determine the number of ways the faces of a regular tetrahedron can be colored with three colors
The diagram shows two vectors that point west and north. What is the magnitude of the resultant vector? 13 miles 17 miles 60 miles 169 miles
Answer:
13
Explanation:
True or false to calculate the wave speed of a wave square the amplitude of the wave
The statement is false because wave speed is not computed by squaring the wave's amplitude. The speed of a wave is influenced by the medium's properties and is often the square root of an elastic property to an inertial property ratio.
The statement 'to calculate the wave speed of a wave square the amplitude of the wave' is false. Wave speed is not calculated by squaring the amplitude of the wave. Instead, wave speed is determined by the properties of the medium through which the wave is traveling and can generally be expressed as the square root of the ratio of an elastic property to an inertial property of the medium.
For example, the speed of sound in air is approximately given by 343.00 m/s at 20°C. The energy and power of a wave, on the other hand, are proportional to the square of the amplitude, but this is not used to calculate the wave's speed.
Therefore, the terms 'amplitude of a wave' and 'wave speed' refer to different aspects of wave properties and should not be confused with each other in physical calculations.
Complete Question:
True or false. To calculate the wave speed of a wave, square the amplitude of the wave.
whats the mass of an atom that has 4 protons , 4 neutrons ,and 4 electrons
The carburetors on inboard mounted gasoline engines must be equipped with an approved back-fire flame arrestor. what purpose does having a back-fire flame arrestor play?
Answer:
To prevent the ignition of gasoline vapors.
Explanation:
A back fire is an explosion that occurs in the air intake system by a running internal combustion engine.
Back-fire flame arrestor is a safety equipment used to prevent the ignition of gasoline vapour.
It stops the flame to avoid an engine backfiring and contact with other fuels. This can led to fire and heavy damage if back fire flame arrestors are not used.
Car a runs a red light and broadsides car b, which is stopped and waiting to make a left turn. car a has a mass of 1,800kg. car b has a mass of 1,500kg. after the impact, the cars stick together and slide away at a speed of 7.1m/s. how fast was car a going when it hit car b?
The law of conservation of momentum tells us that momentum is conserved, therefore total initial momentum should be equal to total final momentum. In this case, we can expressed this mathematically as:
mA vA + mB vB = m v
where, m is the mass in kg, v is the velocity in m/s
since m is the total mass, m = mA + mB, we can write the equation as:
mA vA + mB vB = (mA + mB) v
furthermore, car B was at a stop signal therefore vB = 0, hence
mA vA + 0 = (mA + mB) v
1800 (vA) = (1800 + 1500) (7.1 m/s)
vA = 13.02 m/s
when you are driving on an expressway you must remember that the greatest danger on expressway is what.
Final answer:
The greatest danger on expressways is often the combination of high speeds, aggressive driving, and other driving behaviors that can lead to severe accidents. Patience and safe driving practices are crucial to avoid these dangers. The scenario provided demonstrates an example of aggressive driving that could pose a risk on the expressway.
Explanation:
When driving on an expressway, the greatest danger often arises from high speeds combined with factors such as driver behavior, environmental conditions, and vehicle performance. High-speed environments increase the potential severity of any accident that may occur. Furthermore, situations involving aggressive driving, such as tailgating, improper lane changes, or the act of speeding itself, can lead to collisions. For example, like the scenario of Peter who became frustrated with a slower driver and engaged in tailgating and horn honking, it is essential to practice safe driving behaviors and be patient to avoid accidents.
Regarding the scenario about the rabbit crossing the expressway, if the car is traveling in the furthest lane from the rabbit, there is no guarantee the rabbit would be able to cross all three lanes safely. It is unpredictable due to the potential for multiple vehicles and varying speeds. Animal crossings on highways are hazardous and often result in accidents.
The ________ is filled with electrically charged ions.
If your car breaks down, you should park where the vehicle can be seen for at least _______ feet in each direction.
When your car breaks down, it is recommended to park where the vehicle can be seen for at least 200 feet in each direction. This is important for safety reasons, as it allows other drivers to see your parked car and avoid any potential collisions or accidents. By parking your car where it can be seen from a distance, you are also ensuring that emergency services or roadside assistance can easily locate and help you.
Explanation:When your car breaks down, it is recommended to park where the vehicle can be seen for at least 200 feet in each direction.
This is important for safety reasons, as it allows other drivers to see your parked car and avoid any potential collisions or accidents.
By parking your car where it can be seen from a distance, you are also ensuring that emergency services or roadside assistance can easily locate and help you.
Albert views henry moving by at a constant velocity. henry has a light clock and also a stopwatch which were synchronized when at rest. as albert views these two moving clocks, which of these statements would be true according to albert? the light clock runs slow compared to the stopwatch. the stopwatch runs slow compared to the light clock.
Answer:
The two are still synchronized but run slow
Explanation:
Time flows at a different rate for an object that is moving. The time of the object which is moving is running slower than an object which is stationary. Here, Albert is stationary so time will flow faster for him and for Henry who is moving time will flow slower. This phenomenon is called time dilation
[tex]\Delta t'=\frac{\Delta t}{\sqrt{1-\frac{v^2}{c^2}}}[/tex]
Where,
Δt is the time elapsed for the person who is moving
Δt' is the time elapsed for the person who is stationary
c = Speed of light = 3×10⁸ m/s
v = Velocity of the object which is moving
Answer: D
Explanation:
The two are still synchronized but run slow.
A desk was moved 12 m using 280 j of work. how much force was used to move the desk?
The team monitoring a space probe exploring the outer solar system fi nds that radio transmissions from the probe take 2.53 hours to reach earth. how distant (in meters) is the probe
About where is our solar system located within the milky way galaxy?
A rock thrown with speed 8.50 m/s and launch angle 30.0 ∘ (above the horizontal) travels a horizontal distance of d = 19.0 m before hitting the ground. from what height was the rock thrown? use the value g = 9.800 m/s2 for the free-fall acceleration.
Final answer:
By decomposing the initial velocity into horizontal and vertical components and applying the formulas for projectile motion, we deduced that the rock was thrown from a height of 21.68 meters above the ground.
Explanation:
To solve for the initial height from which the rock was thrown, we need to use the principles of projectile motion. First, we decompose the initial velocity into its horizontal (vx) and vertical (vy) components using trigonometry:
vx = v * cos(θ)
vy = v * sin(θ)
For a velocity of 8.50 m/s and a launch angle of 30°, the horizontal and vertical components are:
vx = 8.50 * cos(30°) = 7.36 m/s
vy = 8.50 * sin(30°) = 4.25 m/s
The horizontal distance travelled d is given by d = vx * t, where t is the time of flight. We can solve for t:
t = d / vx = 19.0 m / 7.36 m/s = 2.58 s
Now we'll use the vertical motion to find the initial height h. The formula for vertical displacement is:
y = vy * t - (1/2) * g * t2
Since the rock hits the ground, vertical displacement y equals the initial height h. Substituting vy, g, and t, we get:
h = y = 4.25 m/s * 2.58 s - (1/2) * 9.800 m/s2 * 2.58 s2
h = 10.97 m - 32.65 m = -21.68 m
Since we're only interested in the magnitude of the height and we know it's an upwards direction, the result is 21.68 m.
This result shows that the rock was thrown from 21.68 meters above the ground level.