All categories

2 years ago

Two students walk in the same direction along a straight path, at a constant speedâone at 0.90 m/s and the other at 1.90 m/s.

Physics

1 answer:

mixer [17]2 years ago

3 0

Answer:

456.143684211 seconds

564.3 m

Explanation:

s = Distance

v = Velocity

Time is given by

$t=\dfrac{s}{v}\\\Rightarrow t=\dfrac{780}{0.9}\\\Rightarrow t=866.67\ s$

$t=\dfrac{s}{v}\\\Rightarrow t=\dfrac{780}{1.9}\\\Rightarrow t=410.526315789\ s$

Difference in time = 866.67-410.526315789 = 456.143684211 seconds

According to the question

$\dfrac{x}{0.9}-\dfrac{x}{1.9}=5.5\times 60\\\Rightarrow x(\dfrac{1}{0.9}-\dfrac{1}{1.9})=330\\\Rightarrow x=\dfrac{330}{\dfrac{1}{0.9}-\dfrac{1}{1.9}}\\\Rightarrow x=564.3\ m$

The students would have to walk 564.3 m

You might be interested in

A car starts from rest and accelerates uniformly for a five seconds along a straight road. If speed obtained by the car is 72 km

Step2247 [10]

Answer:

50 meters

Explanation:

Let's start by converting to m/s. There are 3600 seconds in an hour and 1000 meters in a kilometer, meaning that 72km/h is 20m/s.

$v_f=v_o+at$

Since the car starts at rest, you can write the following equation:

$20=0+a(5) \\\\a=20\div 5=4 m/s^2$

Now that you have the acceleration, you can do this:

$d=v_o+\dfrac{1}{2}at^2$

Once again, there is no initial velocity:

$d=\dfrac{1}{2}(4)(5)^2=2 \cdot 25=50m$

Hope this helps!

8 0

3 years ago

You set your stationary bike on a high 80-N friction-like resistive force and cycle for 30 min at a speed of 8.0 m/s . Your body

stellarik [79]

A) The change in internal chemical energy is $1.15\cdot 10^7 J$

B) The time needed is 1 minute

Explanation:

First of all, we start by calculating the power output of you and the bike, given by:

$P=Fv$

where

F = 80 N is the force that must be applied in order to overcome friction and travel at constant speed

v = 8.0 m/s is the velocity

Substituting,

$P=(80)(8.0)=640 W$

The energy output is related to the power by the equation

$P=\frac{E}{t}$

where:

P = 640 W is the power output

E is the energy output

$t = 30 min \cdot 60 = 1800 s$ is the time elapsed

Solving for E,

$E=Pt=(640)(1800)=1.15\cdot 10^6 J$

Since the body is 10% efficient at converting chemical energy into mechanical work (which is the output energy), this means that the change in internal chemical energy is given by

$\Delta E = \frac{E}{0.10}=\frac{1.15\cdot 10^6}{0.10}=1.15\cdot 10^7 J$

From the previous part, we found that in a time of

t = 30 min

the amount of internal chemical energy converted is

$E=1.15\cdot 10^7 J$

Here we want to find the time t' needed to convert an amount of chemical energy of

$E'=3.8\cdot 10^5 J$

So we can setup the following proportion:

$\frac{t}{E}=\frac{t'}{E'}$

And solving for t',

$t'=\frac{E't}{E}=\frac{(3.8\cdot 10^5)(30)}{1.15\cdot 10^7}=1 min$

Learn more about power and energy:

brainly.com/question/7956557

#LearnwithBrainly

3 0

2 years ago

Which type of wave has a longer wavelength: AM radio waves (with frequencies in the kilohertz range) or FM radio waves (with fre

faltersainse [42]

Answer:

AM has longer wavelength

Explanation:

The relation between the wavelength and teh frequency is given by

v = f x λ

Where, f is the frequency and λ be the wavelength.

It shows that the wavelength is inversely proportional to the frequency.

So, higher the frequency, smaller be the wavelength.

So, FM has high frequency than AM, thus, FM has lower wavelength as compared to AM.

6 0

3 years ago

Reactions that release energy into the environment in the form of heat

meriva

DEFINITION:::::;;The type of reactions in which energy is releases to the environment are called Exothermic reactions.

EXAMPLE::: formation of carbon dioxide and urea formation are actually the examples of exothermic reaction..
Hope it helps

6 0

2 years ago

GIVING BRAINLIEST PLEASE HELP!!

andrey2020 [161]

Answer:

B is the answer!!

Explanation:

4 0

3 years ago