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tensa zangetsu [6.8K]

3 years ago

12

Can the kinetic energy of an object be negative? Can the potential energy of an object be negative? Can a potential energy funct

ion be defined for the force of friction?

1 answer:

IceJOKER [234]3 years ago

5 0

Answer:

Kinetic energy cannot be negative

potential energy is a reference dependent quantity and it can be positive as well as negative both

Since potential energy is defined only for conservative force so it can not be found for friction force

Explanation:

Kinetic energy of an object is given by the formula

$KE = \frac{1}{2}mv^2$

here we know that

m = mass of object that can not be negative

v = speed of the object and since its square is given here so it can not be negative

so Kinetic energy is always positive

potential energy is given as the energy due to the virtue of the position of object

so it is

$\Delta U = -\int F.dr$

so potential energy is a reference dependent quantity and it can be positive as well as negative both

Since potential energy is defined only for conservative force so it can not be found for friction force

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Which is an example of a mixture made of parts that can easily be separated?

Gemiola [76]

Answer

sand and water is an example of a mixture made of parts that can easily be separated

Explatnation

mixture is a material which is formed by mixing two or more different types of materials. No chemical reaction occurs.During combination of two or more type of material to form a mixture.

Example of mixture are

oil and water

sand and water

8 0

3 years ago

point) A circular swimming pool has a diameter of 12 m. The circular side of the pool is 3 m high, and the depth of the water is

Sergio [31]

Answer:

(a) 86.65 J

(b) 149.65 J

Solution:

As per the question:

Diameter of the pool, d = 12 m

⇒ Radius of the pool, r = 6 m

Height of the pool, H = 3 m

Depth of the pool, D = 2.5 m

Density of water, $\rho_{w} = 1000\ kg//m^{3}$

Acceleration due to gravity, g = $9.8\ m/s^{2}$

Now,

(a) Work done in pumping all the water:

Average height of the pool, h = $\frac{H + D}{2}$

h = $\frac{3 + 2.5}{2} = 2.75\ m$

Volume of water in the pool, V = $\pi r^{2}h = \pi \times 6^{2}\times 2.75 = 311.02\ m^{3}$

Mass of water, $m_{w} = \frac{\rho_{w}}{V}$

$m_{w} = \frac{1000}{311.02} = 3.215\ kg$

Work done is given by the potential energy of the water as:

$W = m_{w}gh = 3.215\times 9.8\times 2.75 = 86.65\ J$

(b) Work done to pump all the water through an outlet of 2 m:

Now,

Height, h = 2.75 + 2 = 4.75

Work done, $W = m_{w}gh = 3.215\times 9.8\times 4.75 = 149.65\ J$

7 0

2 years ago

A 3.1-kilogram gun initially at rest is free to

34kurt

The conservation of momentum states that the total momentum in a system is constant if there is no external force acting on the system. The total momentum in the gun bullet system is 0 so it must stay that way.

The momentum of the bullet is mv = 0.015*500=7.5
The momentum of the gun must be the same to keep the total momentum of the system equal to zero, so we know that p = 7.5 for the gun.
Substituting this in we get:

7.5=3.1x
x=7.5/3.1
x=2.42

So the speed of the gun is 2.4m/s.

8 0

3 years ago

Read 2 more answers

Greg throws a 2.8-kg pumpkin horizontally off the top of the school roof in order to hit Mr. H's car. The car has parked a dista

Igoryamba

Answer:

The horizontal velocity is $v = 9.2 m/s$

Explanation:

From the question we are told that

The mass of the pumpkin is $m = 2.8 \ kg$

The distance of the the car from the building's base is $d = 13.4 \ m$

The height of the roof is $h = 10.4 \ m$

The height is mathematically represented as

$h = \frac{1}{2} gt^2$

Where g is the acceleration due to gravity which has a value of $g =9.8 \ m/s^2$

substituting values

$10.4= 0.5 * 9.8 * t$

making the time taken the subject of the formula

$t = \frac{10.4}{0.5 * 9.8 }$

$t = 1.457 \ s$

The speed at which the pumpkin move horizontally can be represented mathematically as

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

substituting values

$v =\frac{13.4}{1.457}$

$v = 9.2 m/s$

7 0

2 years ago

What makes a model not useful?

lina2011 [118]

Answer is b hope this helps

8 0

2 years ago