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3 years ago

If a 2000 N force is used to raise a piano at a rate of 10 m/s2, what is the mass of the piano?

Physics

1 answer:

saveliy_v [14]3 years ago

3 0

Answer:

To solve this problem we will apply the principle of conservation of energy for which we have that the potential energy on a body, is equivalent to the work done on it at the given point. Therefore we will have the following equality

At the same time we know that work is equivalent to the Force applied over a given distance, so,

The potential energy is equivalent to the product between mass, gravity and height. Recall that the product of mass and gravity is equivalent to weight (The same given in the statement)

Equating,

Then,

Replacing,

Therefore the force needed to lift the piano is 600N

Explanation:

HOPE THIS HELPS!!!

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A football player, with a mass of 69.0 kg, slides on the ground after being knocked down. At the start of the slide, the player

White raven [17]

Answer:

(a) -472.305 J

(b) 1 m

Explanation:

(a)

Change in mechanical energy equals change in kinetic energy

Kinetic energy is given by $0.5mv^{2}$

Initial kinetic energy is $0.5\times 69\times 3.7^{2}=472.305 J$

Since he finally comes to rest, final kinetic energy is zero because the final velocity is zero

Change in kinetic energy is given by final kinetic energy- initial kinetic energy hence

0-472.305 J=-472.305 J

(b)

From fundamental kinematic equation

$v^{2}=u^{2}+2as$

Where v and u are final and initial velocities respectively, a is acceleration, s is distance

Making s the subject we obtain

$s=\frac {v^{2}-u^{2}}{-2a}$ but a=\mu g hence

$s=\frac {v^{2}-u^{2}}{-2\mu g}=\frac {0^{2}-3.7^{2}}{-2*0.7*9.81}=0.996796272\approx 1 m$

7 0

3 years ago

Faraday's law states that voltage can be changed by moving the coil out of the magnetic field true or false

NNADVOKAT [17]

As per Faraday's law of induction we know that induced EMF in a conducting closed loop is equal to rate of change in flux in that loop

So here we have

$V = \frac{d\phi}{dt}$

now when we move out a coil from magnetic field then in this case there will be EMF induced in that coil as here magnetic flux is changing with time linked with the coil.

Now this induced voltage will remain constant if coil is moved out uniformly

But it will not remain constant if coil is moved out with non uniform speed

So this statement is not always true

so answer must be

<u>FALSE</u>

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3 years ago

In what substance would heat transfer by conduction work best? Oxygen, iron, water, or alcohol

hodyreva [135]

Iron is the answer. Becaues its solid and it's particles are closest to each other. And well.metals are good at transferring heat.

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3 years ago