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3 years ago

Please help on this one!!

Physics

1 answer:

inysia [295]3 years ago

3 0

The energy transformations that occur as you coast down long hill on a bicycle, including the brakes to make the bike stop at the bottom, is that at the top of the hill you have high GPE AND LOW KE, on your way down you have HIGH KE AND LOW GPE, and at the bottom you have thermal energy due to the stop of the brakes.

the law of conversation of energy and describe the energy transformations that occur as you coast down a long hill on a bicycle and then apply the brakes to make the bike stop at the bottom.

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A tortoise can run with a speed of 0.14 m/s, and a hare can run 20 times as fast. In a race, they both start at the same time, b

Reptile [31]

speed of tortoise is given as v1 = 0.14 m/s

speed of hare is given as v2 = 20*0.14 = 2.8 m/s

now let say the total length of the path is "d"

so the total time taken by the tortoise to cover this

$t = \frac{d}{0.14}$

now given that hare took rest for 1 min

so total time of run for hare is (t - 60)s

so the distance that hare covered is given by

$d - 0.30 = 2.8 * (t - 60)$

now by above two equations

$d - 0.30 = 2.8 * \frac{d}{0.14} - 168$

$168 - 0.30 = (20 - 1)d$

$d = 8.82 m$

and the time t is given by

$t = \frac{8.82}{0.14}$

$t = 63 s$

so part a)

t = 63 s

part b)

d = 8.82 m

4 0

3 years ago

an apple in a tree has a gravitational potential energy of 175J and a mass of 0.36g . how high from the ground is the apple

Neko [114]

The equation for potential energy is denoted as;

Pe = mgh,

where m = the mass, g = acceleration due to gravity, and h = vertical height of the apple. We are given the units for everything but height, which is also what we are solving for. We can then algebraically rearrange our initial equation to solve for h;

h = (Pe)/(mg)

Plug in your given units, and solve!

Post-check:

h = Pe/mg

h = 175J/(0.36g)(-9.81m/s^2)

h = appr. 49.5 meters

Note: Potential energy is a vector quantity; the displacement of the apple will be a negative number, but the distance itself, a scalar quantity, will be the absolute value of that.

5 0

3 years ago

A plane traveled west for 4.0 hours and covered a distance of 4,400 kilometers. What was its velocity? 18,000 km/hr

olga55 [171]

Velocity is the same as the formula for speed, the only difference is velocity has direction. Velocity is distance over time. Given is 4,400 kilometers travelled west in 4 hours. Applying the given equation, we wil have 4,400/4 = 1,100 km/hr west

5 0

3 years ago

Read 2 more answers

A balloon contains 2.3 mol of helium at 1.0 atm , initially at 240 ∘C. What's the initial volume? What's the volume after the ga

pashok25 [27]

A) initial volume
We can calculate the initial volume of the gas by using the ideal gas law:
$p_i V_i = nRT_i$
where
$p_i=1.0 atm=1.01 \cdot 10^5 Pa$ is the initial pressure of the gas
$V_i$ is the initial volume of the gas
$n=2.3 mol$ is the number of moles
$R=8.31 J/K mol$ is the gas constant
$T_i=240^{\circ}C=513 K$ is the initial temperature of the gas

By re-arranging this equation, we can find $V_i$ :
$V_i = \frac{nRT_i}{p_i} = \frac{(2.3 mol)(8.31 J/mol K)(513 K)}{1.01 \cdot 10^5 Pa}=0.097 m^3$

2) Now the gas cools down to a temperature of
$T_f = 14^{\circ}C=287 K$
while the pressure is kept constant: $p_f = p_i = 1.01 \cdot 10^5 Pa$ , so we can use again the ideal gas law to find the new volume of the gas
$V_f = \frac{nRT_f}{p_f}= \frac{(2.3 mol)(8.31 J/molK)(287 K)}{1.01 \cdot 10^5 Pa} = 0.054 m^3$

3) In a process at constant pressure, the work done by the gas is equal to the product between the pressure and the difference of volume:
$W=p \Delta V= p(V_f -V_i)$
by using the data we found at point 1) and 2), we find
$W=p(V_f -V_i)=(1.01 \cdot 10^5 Pa)(0.054 m^3-0.097 m^3)=-4343 J$
where the negative sign means the work is done by the surrounding on the gas.

5 0

3 years ago

How would it be possible for an object to be traveling with a constant speed and still accelerating?

lys-0071 [83]

Yeah!! It's possible for an object by changing it's direction....

4 0

3 years ago