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3 years ago

Which of the following is right?

Physics

1 answer:

barxatty [35]3 years ago

7 0

Scientific theory because it's a theory it's already an answer but it might change depending on the condition.

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Use the work-energy theorem to determine the force required to stop a 1000 kg car moving at a speed of 20.0 m/s if there is a di

Vlad1618 [11]

Answer:

4.44 kN in the opposite direction of acceleration.

Explanation:

Given that, the initial speed of the car is, $u=20m/s$

And the mass of the car is, $m=1000 kg$

The total distance covered by the car before stop, $s=45m$

And the final speed of the car is, $u=0m/s$

Now initial kinetic energy is,

$KE_{i}=\frac{1}{2}mu^{2}$

Substitute the value of u and m in the above equation, we get

$KE_{i}=\frac{1}{2}(1000kg)\times (20)^{2}\\KE_{i}=20000J$

Now final kinetic energy is,

$KE_{f}=\frac{1}{2}mv^{2}$

Substitute the value of v and m in the above equation, we get

$KE_{f}=\frac{1}{2}(1000kg)\times (0)^{2}\\KE_{i}=0J$

Now applying work energy theorem.

Work done= change in kinetic energy

Therefore,

$F.S=KE_{f}-KE_{i}\\F\times 45=(0-200000)J\\F=\frac{-200000J}{45}\\ F=-4444.44N\\F=-4.44kN$

Here, the force is negative because the force and acceleration in the opposite direction.

6 0

3 years ago

When using a different calorimeter, and mixing 50 ml of hot water at 65 degrees c with 60 ml of water in the calorimete

Paha777 [63]

The specific heat capacity of the calorimeter used in mixing the water is determined as 21.87 J/g⁰C.

<h3>Conseervation of energy</h3>

The heat capacity of the calirometer is determined by applying the principle of conservation of energy.

Heat lost by the hot water = Heat gained by the calirometer

$Q _w = Q_c\\\\M_w C_w\Delta \theta _w = M_c C_c\Delta \theta _c$

where;

M is mass

mass = density x volume = ρV

Density of water = 1 g/ml

Mass of hot water = 1 x (50) = 50 g

Mass of water in calorimeter = 1 x (60) = 60 g

<h3>Equilibrium temperature</h3>

$\Delta T_c = 5.5\\\\T - 25 = 5.5\\\\T = 30.5 \ ^0C$

<h3>Specific heat capacity of the calirometer</h3>

$50 \times 4.184 \times (65 - 30.5) = 60 \times C_c \times (30.5 - 25)\\\\7217.4 = 330C_c\\\\C_c = \frac{7217.4}{330} \\\\C_c = 21.87 \ J/g^0C$

Thus, the specific heat capacity of the calorimeter used in mixing the water is determined as 21.87 J/g⁰C.

The complete question is below

When using a different calorimeter, and mixing 50 ml of hot water at

65 degrees C with 60 ml of water in the calorimeter at 25 degrees C, the temperature of the calorimeter increased by 5.5 degrees C.

a. Calculate the heat capacity of this calorimeter?

Learn more about heat capacity here: brainly.com/question/16559442

5 0

2 years ago

Suggest a situation where we can obtain more than one shadow of an object at a time?

Murljashka [212]

Answer:

We can obtain more than one shadow of an object if light from more than one source falls on it. [For example during a match being played in a stadium multiple shadows of players are seen].

Explanation:

nah-

4 0

3 years ago

It takes less time to manually move patients than to use lift equipment. Is this statement a myth or fact?

sergejj [24]

Fact. Using lift equipment would take longer.

7 0

4 years ago

Read 2 more answers

Anyone pls ASAP it’s so important I will give brainlist or anuthing pls

maxonik [38]

Well the mean is when you add up the answers together and divide by how many there is so
1)the length is 10.2
2)the width is 3.25

4 0

3 years ago