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1 year ago

A car has a kinetic energy of 41.6 kJ.

1 answer:

4 0

K=1/2 mv2

M=?

41.6kj convert to joules by multiplying by 1000 so it will be 41,600J because the unit of kinetic energy is in joules.

41,600=1/2(m)(8)

Arrange the equation it will be:

M= 41,600/4 = 10,400

Final answer is:
m= 10,400 kg

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A pendulum of length L=36.1 cm and mass m=168 g is released from rest when the cord makes an angle of 65.4 degrees with the vert

pychu [463]

(a) -0.211 m

At the beginning the mass is displaced such that the length of the pendulum is L = 36.1 cm and the angle with the vertical is

$\theta=65.4^{\circ}$

The projection of the length of the pendulum along the vertical direction is

$L_y = L cos \theta = (36.1 cm)(cos 65.4^{\circ})=15.0 cm$

the full length of the pendulum when the mass is at the lowest position is

L = 36.1 cm

So the y-displacement of the mass is

$\Delta y = 15.0 cm - 36.1 cm = -21.1 cm = -0.211 m$

(b) 0.347 J

The work done by gravity is equal to the decrease in gravitational potential energy of the mass, which is equal to

$\Delta U = mg \Delta y$

where we have

m = 168 g = 0.168 kg is the mass of the pendulum

g = 9.8 m/s^2 is the acceleration due to gravity

$\Delta y = 0.211 m$ is the vertical displacement of the pendulum

So, the work done by gravity is

$W=(0.168 kg)(9.8 m/s^2)(0.211 m)=0.347 J$

And the sign is positive, since the force of gravity (downward) is in the same direction as the vertical displacement of the mass.

(c) Zero

The work done by a force is:

$W=Fd cos \theta$

where

F is the magnitude of the force

d is the displacement

$\theta$ is the angle between the direction of the force and the displacement

In this situation, the tension in the string always points in a radial direction (towards the pivot of the pendulum), while the displacement of the mass is tangential (it follows a circular trajectory): this means that the tension and the displacement are always perpendicular to each other, so in the formula

$\theta=90^{\circ}, cos \theta = 0$

and so the work done is zero.

5 0

2 years ago

Explain why an egg thrown at a concrete wall will break, but an egg thrown at a sheet hanging from the ceiling will not. (Be sur

Firlakuza [10]

An egg thrown at a concrete wall will break, but an egg thrown at a sheet hanging from the ceiling will not due to high momentum and acceleration.

<h3>Why an egg thrown at a concrete wall will break?</h3>

An egg thrown at a concrete wall will break, but an egg thrown at a sheet hanging from the ceiling will not because the momentum and acceleration increases when the egg is thrown downward due to gravity but when we throw an egg in the vertical direction, they move against gravity so the momentum and acceleration decreases.

So we can conclude that an egg thrown at a concrete wall will break, but an egg thrown at a sheet hanging from the ceiling will not due to high momentum and acceleration.

Learn more about momentum here: brainly.com/question/7538238

#SPJ1

4 0

1 year ago

Which liquid will evaporate the fastest water salt water pepsi and gatorade?

MArishka [77]

The liquid that will evaporate the quickest would be water.
<em>~The rest are mixtures, and have more ingrediants in them, therefore the answer should be water. (in which it has no other ingrediants in it but water itself)</em>

6 0

2 years ago

Calculate the potential energy of a 5 kg object sitting at the top of a 2 meter ramp.

trapecia [35]

The formula used to find potential energy is <em>P.E. = M * G * H</em> (P.E. is potential energy, M is mass, G is gravitational pull, and H is height). So the answer to your question is <em>5 * 9.8 * 2</em>, which equals 98.

5 0

2 years ago

Simone is walking her dog on a leash. The dog is pulling with force of 34 N to the right and simone is pulling backward with a f

e-lub [12.9K]

I do not understand the full question, however if you are wondering which way Simone and the dog will go, they will go right because the force of 34 N from the dog is higher than the force of 16 N from Simone.

4 0

2 years ago