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3 years ago

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Car A has a mass of 1,000 kg and is traveling 60 km/hr. Car B has a mass of 2,000 kg and is traveling 30 km/hr. Compare the kine

tic energy of car A with that of car B?
A) equal
B) half as much
C) twice as much
D) four times as much

2 answers:

givi [52]3 years ago

7 0

Answer:

twice as much

Explanation:

Using the formula for the amount of kinetic energy: K.E. = 1/2 m v2. You would find that car A has twice as much energy as car B.

Artyom0805 [142]3 years ago

3 0

Answer:

c) Twice as much

Explanation:

As we know that kinetic energy is given by the formula

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

here we know that

m = mass of the object

v = speed of the object

so here we will have kinetic energy of Car A

$K = \frac{1}{2}(1000)(60^2)$

$K_a = 1.8 \times 10^6$

now we have kinetic energy of B is given as

$K_b = \frac{1}{2}(2000)(30^2)$

$K_b = 0.9 \times 10^6$

So kinetic energy of Car A is double that of Kinetic energy of car B

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A refrigerator is being pulled up a ramp with a horizontal force P, which acts at the top corner. The refrigerator has a mass of

vaieri [72.5K]

Answer:

(a) P = 459.055 N.

(b) the refrigerator tips.

Explanation:

Given, the angle of ramp is 20°.

When the weight of refrigerator is resolved in directions parallel and perpendicular to ramp, 75×g×sin(20°) and 75×g×cos(20°).

⇒ normal contact force is 75×g×cos(20°).

⇒ frictional force is 0.3×75×g×cos(20°) = 207.414 N

so, total opposite force is 207.414 + 75×g×sin(20°) = 459.055 N.

so, the force needed is P = 459.055 N

And as the moment due to both opposite force and P force are in same direction the refrigerator tips rather than just sliding.

4 0

3 years ago

A 2.0 m × 4.0 m flat carpet acquires a uniformly distributed charge of −10 μC after you and your friends walk across it several

mamaluj [8]

Answer:

The charge on the dust particle is $q_d = 6.94 *10^{-13} \ C$

Explanation:

From the question we are told that

The length is $l = 2.0 \ m$

The width is $w = 4.0 \ m$

The charge is $q = -10\mu C= -10*10^{-6} \ C$

The mass suspended in mid-air is $m_a = 5.0 \mu g = 5.0 *10^{-6} \ g = 5.0 *10^{-9} \ kg$

Generally the electric field on the carpet is mathematically represented as

$E = \frac{q}{ 2 * A * \epsilon _o}$

Where $\epsilon _o$ is the permittivity of free space with value $\epsilon_o = 8.85*10^{-12} \ \ m^{-3} \cdot kg^{-1}\cdot s^4 \cdot A^2$

substituting values

$E = \frac{-10*10^{-6}}{ 2 * (2 * 4 ) * 8.85*10^{-12}}$

$E = -70621.5 \ N/C$

Generally the electric force keeping the dust particle on the air equal to the force of gravity acting on the particles

$F__{E}} = F__{G}}$

=> $q_d * E = m * g$

=> $q_d = \frac{m * g}{E}$

=> $q_d = \frac{5.0 *10^{-9} * 9.8}{70621.5}$

=> $q_d = 6.94 *10^{-13} \ C$

4 0

3 years ago

A crane is used to lower weights into a lake for an underwater construction project. Determine the tension in the cable of the c

atroni [7]

Answer:

Tension in the cable = 591292.8 N or 591.3 kN

Explanation:

Tension in the cable = Weight of object in air - upthrust/bouyancy due to the liquid

Weight of object in air = mass * acceleration due to gravity, g

Since mass is not given, it is obtained from the formula, mass = density * volume

Volume of the sphere = 4/3πr³ where r, radius = 2 m; π = 22/7

volume = 4/3 * 22/7 * (2m)³

volume of sphere = 33.52 m³

Density of concrete sphere = specific gravity * density of water

where, specific gravity = 2.8, density of water = 1000 kg/m³

density of concrete = 2.8 * 1000 kg/m³

density of concrete = 2800 kg/m³

acceleration due to gravity, g = 9.8 m/s²

Thus, weight of concrete = 2800 kg/m³ * 33.52 m³ * 9.8 m/s² = 919788.8 N

Upthrust = density of water * volume of sphere * g

Upthrust = 1000 kg/m³ * 33.52 m³ * 9.8 m/s² = 328496 N

The tension in the cable is the calculated as below;

Tension in the cable = Weight of object in air - upthrust/bouyancy due to the liquid

Tension in cable = 919788.8 N - 328.496 N = 591292.8 N

Therefore, tension in the cable is 591292.8 N or 591.3 kN

5 0

2 years ago

What is the displacement of the runner in 4 laps? *<br> 2 point

Serhud [2]

Answer:

There is no displacement.

Explanation:

Because the runner is running laps and returning to the original place, there is no displacement as displacement is relative to the change in location from the original position.

Hope this helps. . .

ly UwU

3 0

2 years ago

Tamsen is interested in history, and read that because of its regular period, the pendulum constituted the basis of the most acc

geniusboy [140]

We will apply the concept of period in a pendulum, defined as the product between 2 $\pi$ by the square root of the length over gravity, this is mathematically

$T = 2\pi \sqrt{\frac{L}{g}}$

Here,

T = Period

L = Length

g = Acceleration due to gravity

For the period to be 1 second, then we must look for the necessary length for such a requirement so

$1 = 2\pi \sqrt{\frac{L}{9.8}}$

$(\frac{1}{2\pi})^2 = \frac{L}{9.8}$

$L = 9.8(\frac{1}{2\pi})^2$

$L = 0.2482m$

The meter's length would be slight less than one-fourth of its current length. Also, the number of significant digits depends only on how precisely we know g, because the time has been defined to be exactly 1s.

Therefore the correct answer is C.

3 0

3 years ago