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3 years ago

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An 80.0 kg hiker walks a distance of 400.0 m along a road that slopes 5.0 degrees upward, and then stops. What is the hiker's fi

nal gravitational potential energy relative to her original position? You may use a trigonometry table

1 answer:

lana66690 [7]3 years ago

4 0

The height difference is found by
$\delta H=400sin(5 \°)=34.86m$
Then the change in potential energy is
$E=mgh=(80.0kg)(9.8 \frac{kgm}{s^2})(34.86)= 27332J$

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A 4.6-kg block of ice originally at 263 K is placed in thermal contact with a 15.7-kg block of silver (cAg = 233 J/kg-K) which i

Viktor [21]

Answer:

temperature at 326.44 K system achieve equilibrium

Explanation:

given data

mass of block of ice = 4.6 kg

temperature = 263 K

thermal contact = 15.7-kg

specific heat of silver cAg = 233 J/kg-K

initially temperature = 1052 K

to find out

what temperature will the system achieve equilibrium

solution

first we consider final temperature of the system is T

we know that specific heat of water (C w) = 4186 J(kg K)

and

specific heat of ice ( C i ) = 2030 J/(kg K)

and

latent heat of fusion of ice ( Lf ) = 3.33 × $10^{5}$ J/kg

and we know that system is insulated

so heat lost by silver = heat generated by ice .................1

so we can say

mass of silver × specific heat of silver × ( initial temp - final temp ) = mass of ice × specific heat of ice × ( ice temp ) + mass of ice × latent heat of fusion of ice + mass of ice × specific heat of water × (final temperature )

put here value we get

mass of silver × specific heat of silver × ( initial temp - final temp ) = mass of ice × specific heat of ice × ( ice temp ) + mass of ice × latent heat of fusion of ice + mass of ice × specific heat of water × (final temperature )

15.7 × 233 × ( 1052 - T ) = 4.6 × 2030 × 10 + 4.6 × 3.33 × $10^{5}$ + 4.6 × 4286 × ( T - 273 )

solve we get

T = 326.44 K

so temperature at 326.44 K system achieve equilibrium

7 0

3 years ago

Stella is driving down a steep hill. she should keep her car __________ to help _________.

Softa [21]

Answer:

Stella is driving down a steep hill. She should keep her car in a lower gear to help slow her vehicle.

Explanation:

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2 years ago

PtichkaEL [24]

Answer:

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2 years ago

The speed of an arrow fired from a compound

san4es73 [151]

Answer:

A.) The arrow`s range is 624,996 m

B.) The arrow`s range is 846.887 m, when the horse is galloping

Explanation:

We have a case of oblique movement. In these cases the movement in the X axis is a Uniform Rectelinear Movement (URM), and a Uniform Accelerated Movement (UAM) in the Y axis.

By the way, the equations that we use for the X axis will be from URM, and those for the Y axis wiil be from UAM.

<u>Equations</u>

X axis:

$X=v_{ox}*t$

$v_{0x} =v_0cos(\alpha)$

Y axis:

$Y= Y_0 +v_{y0} t - \frac{g}{2} t^2$

A.) First, it is necessary to know t, total time.

To figure out t value, we use UAM, since time is determined by this movement.

Now, at the end of the movement, $Y=0$ , then

$0= Y_0 +v_{y0} t - \frac{g}{2} t^2$

$0=2.4m+79m/s*sin(39)t-(1/2*9.81m/s^2)t^2$

Caculate the segcond degree equation to obtain the two possible values for t:

$t_1= 10.18 \\t_2= -0.04046$

But, in physics, time it could not be negative, so we take $t_1= 10.18$

Caculate now:

$X=79m/s*cos(\39)*10.18s= 624.996 m$

B.) Now, the narrow has an additional speed, that could be sum to the speed due to the bow.

$v_0= 79m/s+13m/s= 92m/s$

Using the same procedure that item A, caculate X

First, we need to know the new time

$0=2.4m+92m/s*sin(39)t-(1/2*9.81m/s^2)t^2$

And we obtain:

$t_1=11.845s\\t_2=-0.041s$

One more time, we take the positive time: $t_1=11.845s$

Finally:

$X=92m/s *cos(39)*11.845s=846.887 m$

6 0

3 years ago

the hydrometer with the density of liquid to be 800 kg metre per square is the volume of the submerged part of the hydrometer is

julia-pushkina [17]

Answer:

Mass = 0.04 Kg

Explanation:

Given the following data;

Density = 800 kg/m³

Volume = 5 * 10^{-5} m³

To find the mass of the object;

Density can be defined as mass all over the volume of an object.

Simply stated, density is mass per unit volume of an object.

Mathematically, density is given by the formula;

$Density = \frac {mass}{volume}$

Making mass the subject of formula, we have;

$Mass = density * volume$

Substituting the values into the formula, we have;

$Mass = 800 * 5 * 10^{-5}$

Mass = 0.04 Kg

8 0

3 years ago