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2 years ago

How much kinetic energy does an object have that is moving at a rate of 30 m/s and has a mass of 4000 kg ?

Physics

1 answer:

DaniilM [7]2 years ago

3 0

Answer:

K = 1800 kJ

Explanation:

Given that,

The speed of the object, v = 30 m/s

Mass of the object, m = 4000 kg

We need to find the kinetic energy of the object. The formula for the kinetic energy is given by :

$K=\dfrac{1}{2}mv^2\\\\K=\dfrac{1}{2}\times 4000\times 30^2\\\\K=1800000\\\\or\\\\K=1800\ kJ$

So, the required kinetic energy is equal to 1800 kJ.

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What is transferred through sound waves?

alexandr402 [8]

Answer:

Sound waves transfer energy by causing successive compressions and rarefactions in the particles of the medium without transporting the medium particles themselves. Sound in solids can also manifest as transverse waves, causing crests and troughs in the propagation medium.

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3 years ago

A net force of 345 N accelerates a boy on a sled at 3.2 m/s^2 . What is combined mass of the sled

Daniel [21]

Answer:

Mass, m = 26.54kg

Explanation:

Net force can be defined as the vector sum of all the forces acting on a body or an object i.e the sum of all forces acting simultaneously on a body or an object.

Mathematically, net force is given by the formula;

$Fnet = Fapp + Fg$

Where;

Fnet is the net force

Fapp is the applied force

Fg is the force due to gravitation

Given the following data;

Net force, Fnet = 345

Acceleration, a = 3.2m/s²

To find mass;

Fnet = Fapp + Fg

Fnet = ma + mg

Fnet = m(a+g)

m = Fnet/(a+g)

We know that acceleration due to gravity, g = 9.8m/s²

Substituting into the equation, we have;

m = 345/(3.2 + 9.8)

m = 345/13

Mass, m = 26.54kg

6 0

2 years ago

Which electromagnetic wave enables us to see objects?

Valentin [98]

Choose visible light

3 0

3 years ago

Read 2 more answers

answer questions1) The south pole of the steel magnet will be brought closer to the iron nail head. Which pole will be at the po

Anvisha [2.4K]

Answer:

North pole

Explanation:

According to the law of magnetism:

Unlike poles attract while like poles repel

Since the south pole of the steel is brought near the nail, and the nail is meant to attract the steel magnet, the nail domain realigns itself to produce a pole opposite to the pole of the steel magnet brought near it.

Since the North pole is the opposite of the south pole, the North pole will be at the pointed end of the nail so that it can attract the steel magnet.

8 0

1 year ago

A 0.0450 kg bullet is accelerated from rest to a speed of 425 m/s in a 2.25 kg rifle (which is inititally at rest). The pain of

Mrac [35]

Answer:

If the rifle is held loosely away from the shoulder, the recoil velocity will be of -8.5 m/s, and the kinetic energy the rifle gains will be 81.28 J.

Explanation:

By momentum conservation, and given the bullit and the recoil are in a straight line, the momentum analysis will be unidimentional. As the initial momentum is equal to zero (the masses are at rest), we have that the final momentum equals zero, so

$0=P_{f}=m_{b} *v_{b}+m_{r}*v_{r}$

now we clear $v_{r}$ and use the given data to get that

$v_{r}=-8.5\frac{m}{s}$

But we have to keep in mind that the bullit accelerate from rest to a speed of 425 m/s, then if the rifle were against the shoulder, the recoil velocity would be a fraction of the result obtained, but, as the gun is a few centimeters away from the shoulder, it is assumed that the bullit get to its final velocity, so the kick of the gun, gets to its final velocity $\bold{v_{r}}$ too.

Finally, using $v_{r}$ we calculate the kinetic energy as

$K=\frac{1}{2}m_{r}v_{r}^{2}=81.28J$

3 0

3 years ago