Physics : asked on denym58

12.04.2022

Police driving with a velocity of 50 m/s decide to chase a speeder who is 3 km ahead and moving at 55 m/s. The police car accelerates at 2 m/s2. Instantly the speeder becomes aware that he is being chased and starts to accelerate at 1 m/s2. How much time (in s) passes until the police catch the speeder

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24.06.2023, solved by verified expert

Bhaskar Singh Bora

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The time that passes until the police catch the speeder is 82.6204 seconds.

Explanation:

A body performs a uniformly accelerated rectilinear motion or uniformly varied rectilinear motion when its path is a straight line and its acceleration is constant. This implies that the speed increases or decreases its modulus in a uniform way.

The position is calculated by the expression:

x = x0 + v0*t + 1/2*a*t²

where:

x0 is the initial position. v0 is the initial velocity. a is the acceleration. t is the time interval in which the motion is studied.

First, let’s look at the police car’s equations of motion. In this case:

x0= 0 v0= 50 m/s a= 2 m/s²

So: x = 50 m/s*t + 1/2*2 m/s²*t²

Now for the speeder’s car’s equations of motion you know:

x0= 3 km= 3,000 m v0= 55 m/s a= 1 m/s²

So: x = 3,000 m + 55 m/s*t + 1/2*1 m/s²*t²

When the police catch the speeder they are both in the same position. So:

50 m/s*t + 1/2*2 m/s²*t²= 3,000 m + 55 m/s*t + 1/2*1 m/s²*t²

Solving:

0= 3,000 m + 55 m/s*t + 1/2*1 m/s²*t² - 50 m/s*t - 1/2*2 m/s²*t²

0= 3,000 + 55 *t + 1/2*t² - 50*t - 1*t²

0= 3,000 + 55 *t - 50*t - 1*t² + 1/2*t²

0= 3,000 + 5*t - 1/2*t²

Applying the quadratic formula:

x1= -72.6209

and x2= 82.6209

Since you are calculating the value of a time and it cannot be negative, then the time that passes until the police catch the speeder is 82.6204 seconds.

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Physics

Police driving with a velocity of 50 m/s decide to chase a speeder who is 3 km ahead and moving at 55 m/s. The police car accelerates at 2 m/s2. Instantly the speeder becomes aware that he is being chased and starts to accelerate at 1 m/s2. How much time (in s) passes until the police catch the speeder

Step-by-step answer

P Answered by PhD

The time that passes until the police catch the speeder is 82.6204 seconds.

Explanation:

The position is calculated by the expression:

x = x0 + v0*t + 1/2*a*t²

where:

x0 is the initial position. v0 is the initial velocity. a is the acceleration. t is the time interval in which the motion is studied.

First, let’s look at the police car’s equations of motion. In this case:

x0= 0 v0= 50 m/s a= 2 m/s²

So: x = 50 m/s*t + 1/2*2 m/s²*t²

Now for the speeder’s car’s equations of motion you know:

x0= 3 km= 3,000 m v0= 55 m/s a= 1 m/s²

So: x = 3,000 m + 55 m/s*t + 1/2*1 m/s²*t²

When the police catch the speeder they are both in the same position. So:

50 m/s*t + 1/2*2 m/s²*t²= 3,000 m + 55 m/s*t + 1/2*1 m/s²*t²

Solving:

0= 3,000 m + 55 m/s*t + 1/2*1 m/s²*t² - 50 m/s*t - 1/2*2 m/s²*t²

0= 3,000 + 55 *t + 1/2*t² - 50*t - 1*t²

0= 3,000 + 55 *t - 50*t - 1*t² + 1/2*t²

0= 3,000 + 5*t - 1/2*t²

Applying the quadratic formula:

$x1,x2=\frac{-5+-\sqrt{5^{2}-4*(-\frac{1}{2})*3000 } }{2*(-\frac{1}{2} )}$

x1= -72.6209

and x2= 82.6209

Since you are calculating the value of a time and it cannot be negative, then the time that passes until the police catch the speeder is 82.6204 seconds.

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Bees can see into the ultraviolet region of the electromagnetic spectrum. Compared with humans, bees can sense electromagnetic waves that have a lower frequency and a shorter wavelength. a higher frequency and a longer wavelength. a lower frequency and a longer wavelength. a higher frequency and a shorter wavelength.

Step-by-step answer

P Answered by Specialist

Options:
a. a lower frequency and a shorter wavelength.
b. a higher frequency and a longer wavelength.
c. a lower frequency and a longer wavelength.
d. a higher frequency and a shorter wavelength

Answer:
d. a higher frequency and a shorter wavelength

Explanation:
The frequency of a wave is inversely proportional to its wavelength. That means that waves with a high frequency have a short wavelength, while waves with a low frequency have a longer wavelength. Light waves have very, very short wavelengths.
For example, Gamma rays have the highest energies, the shortest wavelengths, and the highest frequencies. Radio waves, on the other hand, have the lowest energies, longest wavelengths, and lowest frequencies of any type of EM radiation.
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The system shown above consists of two identical blocks that are suspended using four cords, each of a different length. Which of the following claims are true about the magnitudes of the tensions in the cords?

Step-by-step answer

P Answered by Specialist

Answer: Option B and C are True.

Explanation:
The weight of the two blocks acts downwards.
Let the weight of the two blocks be W. Solving for T₁ and T₂:
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w = T₂/cos 30° ----(2);
equating (1) and (2)
T₁/cos 60° = T₂/cos 30°;
T₁ cos 30° = T₂ cos 60°;
T₂/T₁ = cos 30°/cos 60°;
T₂/T₁ =1.73.
Therefore, option a is false since T₂ > T₁.
Option B is true since T₁ cos 30° = T₂ cos 60°.
Option C is true because the T₃ is due to the weight of the two blocks while T₄ is only due to one block.
Option D is wrong because T₁ + T₂ > T₃ by simple summation of the two forces, except by vector addition.
Answer: Option B and C are True.

Explanation:
The weight of the two blocks acts downwards.
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Step-by-step answer

P Answered by PhD

Answer:

Option D

Step-by-step explanation:

D.
Heat each cube to the same temperature, place each cube into different containers with 500 grams of water at the same temperature, and measure the temperature of the water.

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Step-by-step answer

P Answered by PhD

The question specifies the diameter of the screw, therefore the IMA of this screw is 0.812? / 0.318 = 8.02

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Step-by-step answer

P Answered by PhD

Answer:
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Explanation:
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Next find the time it takes to go that distance , s = ut +[1/2] at^2
8.7^2/4.8 = 8.7t +[1/2] [ -2.4]t^2 , rearrange and
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Note:
The term differential is used in calculus to refer to an infinitesimal (infinitely small) change in some varying quantity. For example, if x is a variable, then a change in the value of x is often denoted Δx (pronounced delta x). The differential dx represents an infinitely small change in the variable x.

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Step-by-step answer

P Answered by PhD

First sum applied the Newton's second law motion: F = ma
Force = mass* acceleration
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such that, (mass*velocity)/time=momentum/time
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An electrical kettle supplies 20,000j of energy to heat 0.5kg of water. What is the temperature change? The specific heat capacity of water is 4200j/kg.

Step-by-step answer

P Answered by PhD

The change in temperature is 9.52°CExplanation:Since, the heat supplied by the electric kettle is totally used to increase the temperature of the water.Thus, from the law of conservation of energy can be stated as:Heat Supplied by Electric Kettle = Heat Absorbed by WaterHeat Supplied by Electric Kettle = m C ΔTwhere,Heat Supplied by Electric Kettle = 20,000 JMass of water = m = 0.5 kgSpecific Heat Capacity of Water = C = 4200 J/kg.°CChange in Temperature of Water = ΔTTherefore,20,000 J = (0.5 kg)(4200 J/kg.°C) ΔTΔT = 20,000 J/(2100 J/°C)ΔT = 9.52°C

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Step-by-step answer

P Answered by PhD

Weight of barbell (m) = 100 kg
Uplifted to height (h) = 2m
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Step-by-step answer

P Answered by PhD

The horizontal and vertical motions of balloons are independent from each other.
Let vertical component of initial velocity U' horizontal component of initial velocity U"
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