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2 years ago

A 8kg cat is running 4m/s. how much kinetic energy does it have?

2 answers:

7 0

The formula for kinetic energy is, ${ E }_{ k }=\frac { 1 }{ 2 } \cdot m\cdot { v }^{ 2 }$
where m is mass and v is velocity.

Let's plug the given values in the formula.

${ E }_{ k }=\frac { 1 }{ 2 } \cdot m\cdot { v }^{ 2 }\\ \\ { E }_{ k }=\frac { 1 }{ 2 } \cdot 8\cdot { 4 }^{ 2 }\\ \\ { E }_{ k }=\frac { 1 }{ 2 } \cdot 8\cdot 16\\ \\ { E }_{ k }=4\cdot 16\\ \\ { E }_{ k }=64\quad \\ \\$

It's kinetic energy is 64 Joules.

olya-2409 [2.1K]2 years ago

6 0

Kinetic energy = (1/2) (mass) (speed)²

Kinetic energy = (1/2) (8 kg) (4 m/s)² =

      (4 kg) (16 m²/s²) =

   64 (kg-m/s²) (m) = 64 newton-m = <em>64 joules</em>

And may I say . . . that is one fat cat !   (about 17.6 pounds)

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The Lamborghini Huracan has an initial acceleration of 0.85g. Its mass, with a driver, is 1510 kg. If an 80 kg passenger rode al

SashulF [63]

Answer:

7.9 $\frac{m}{s^{2} }$

Explanation:

Take the fact that mass is inversely proportional to accelertation:

m ∝ a

Therefore m = a, but because we are finding the change in acceleration, we would set our problem up to look more like this:

$\frac{m_{1} }{m_{2} } = \frac{a_{2} }{a_{1} } \\$

Using algebra, we can rearrange our equation to find the final acceleration, $a_{2}$ :

$a_{2} = \frac{a_{1}*m_{1} }{m_{2} } \\$

Before plugging everything in, since you are being asked to find acceleration, you will want to convert 0.85g to m/s^2. To do this, multiply by g, which is equal to 9.8 m/s^2:

0.85g * 9.8 $\frac{m }{s^{2} }$ = 8.33 $\frac{m }{s^{2} }$

Plug everything in:

7.9 $\frac{m }{s^{2} }$ = $\frac{ 8.33\frac{m}{s^{2} }*1510kg }{1590kg}$

(1590kg the initial weight plus the weight of the added passenger)

8 0

2 years ago

A chair of mass 12.0 kg is sitting on the horizontal floor; the floor is not frictionless. You push on the chair with a force F

Tanya [424]

Answer: Normal force, N = 141.64 Newton

Explanation:

All the forces acting on the system and described in free body diagram are:

1) gravitational pull in downward direction

2) Normal force in upward direction

3) External force of 40 N acting at an angle of 37° with the horizontal can be resolved in two rectangular components:

i) F Cos 37° along the horizontal plane in forward direction and

ii) F Sin 37° along the vertical plane in downward direction

Applying the Newton's second law, net forces in the vertical plane are:

Net force, f = N - (mg + F Sin 37°)

As there is no acceleration in the vertical plane hence, net force f = 0.

So,

N - (mg + F Sin 37°) = 0

Adding (mg + F Sin 37°) both the sides in above equation, we get

N = mg + F Sin 37°

N = 12 $\times$ 9.8 + 40 $\times$ 0.601 because (Sin 37° = 0.601)

N = 117.6 + 24.04

N = 141.64 Newton

3 0

2 years ago

Compute the mean and maximum velocities for a liquid with a flow rate of 20 L/min in a 1.5-in nominal diameter sanitary pipeline

vlada-n [284]

Answer:

Mean velocity = 0.292 m/s

Maximum velocity = 0.584 m/s

The flow is laminar as Re = 229.2

Explanation:

D = 1.5 inches = 0.0381 m

Q = volumetric flow rate = 20 L/min = 0.000333 m³/s

Q = A × v

A = Cross sectional Area = πD²/4 = π(0.0381)²/4 = 0.00114 m²

v = average velocity

v = Q/A = 0.000333/0.00114 = 0.292 m/s

For flow in circular pipes, maximum velocity = 2 × average velocity = 2 × 0.292 = 0.584 m/s

To check if the flow is laminar or turbulent, we need its Reynolds number

Re = (ρvD)/μ

ρ = 1030 kg/m

v = 0.292 m/s

D = 1.5 inches = 0.0381 m

μ = 50 cP = 0.5 poise = 0.05 Pa.s

Re = (1030 × 0.292 × 0.0381)/0.05 = 229.2

For laminar flow, Re < 2100

For turbulent flow, Re > 4000

And 229.2 < 2100, hence, this flow is laminar.

7 0

2 years ago

A 50-kg platform diver hits the water below with a kinetic energy of 5000 Joules. The height (relative to the water) from which

artcher [175]

Answer:

h = 10 m

Explanation:

given,

mass of platform = 50 Kg

Kinetic energy = 5000 J

height from which the diver dove = ?

taking acceleration due to gravity = 10 m/s²

using conservation of energy

Kinetic energy is converted into mechanical energy

K.E = P.E

K.E = m g h

5000 = 50 x 10 x h

500 h = 5000

$h = \dfrac{5000}{500}$

h = 10 m

The height from which the diver dove is equal to h = 10 m

6 0

2 years ago

A radar used to detect the presence of aircraft receives a pulse that has reflected off an object 5 ✕ 10−5 s after it was transm

Sunny_sXe [5.5K]

Answer:

7500 m

Explanation:

The radar emits an electromagnetic wave that travels towards the object and then it is reflected back to the radar.

We can call L the distance between the radar and the object; this means that the electromagnetic wave travels twice this distance, so

d = 2L

In a time of

$t=5\cdot 10^{-5}s$

Electromagnetic waves travel in a vacuum at the speed of light, which is equal to

$c=3.0\cdot 10^8 m/s$

Since the electromagnetic wave travels with constant speed, we can use the equation for uniform motion ,so:

$d=vt$ (1)

where

$v=c=3.0\cdot 10^8 m/s$

$t=5\cdot 10^{-5}s$

$d=2L$ , where L is the distance between the radar and the object

Re-arranging eq(1) and substituting, we find L:

$L=\frac{vt}{2}=\frac{(3.0\cdot 10^8)(5\cdot 10^{-5})}{2}=7500 m$

7 0

2 years ago