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3 years ago

Can anyone help me with this please

Physics

1 answer:

Anastasy [175]3 years ago

7 0

Answer:

1270 J

Explanation:

Recall that the mechanical energy of a system is the addition of the Potential energy and the Kinetic energy at any given time.

As the skier descends, potential energy is converted into kinetic energy, but the total mechanical energy should remain the same.

We see that it is not the case, so that difference is what has gone into thermal energy; 19500 J - 18230 J = 1270 J

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Is a frame of reference usually moving

balu736 [363]

A reference frame can be moving. To make sure that newtons laws still apply, the reference frame must not be accelerating.

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3 years ago

A machine produces 4,000 J of work in 5 seconds. how much power does the machine produce.

ad-work [718]

Explanation:

Power is defined as the work done per unit time or

$P = \dfrac{\Delta W}{\Delta t}$

$\;\;\;\;= \dfrac{4000\:\text{J}}{5\:\text{s}} = 800\:\text{Watts}$

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2 years ago

20. A car battery with a 12-V emf and an internal resistance of 0.050 Ω is being charged with a current of 60 A. Note that in th

topjm [15]

Answer:

Part a)

V = 15 Volts

Part b)

P = 180 Watt

Part c)

Rate = 720 Watt

Explanation:

Part a)

When battery is in charging then the potential difference of the terminals of cell is given by

$\Delta V = EMF + iR$

here we know that

EMF = 12 volts

i = 60 A

r = 0.050 ohm

now we have

$\Delta V = 12 + (0.050)(60) = 15 Volts$

Part b)

Rate of thermal energy dissipated is the energy which is dissipating across the resistor

so here we have

$P = i^2 R$

$P = (60^2)(0.05)$

P = 180 Watt

Part c)

Rate at which Energy stored inside the cell is the rate of electrical energy that is converted into the chemical energy

$Rate = EMF \times i$

$Rate = (12)(60)$

$Rate = 720 Watt$

6 0

3 years ago

A football is thrown due north across a 40 meter river and it takes 2 seconds to cover that distance.

Alexxx [7]

Answer:

I. Speed = 20m/s

II. Velocity = 20m/s due North.

Explanation:

Given the following data;

Distance = 40m

Time = 2secs

To find the speed;

Mathematically, speed is given by the formula;

$Speed = \frac{distance}{time}$

Substituting into the equation, we have;

$Speed = \frac{40}{2}$

Speed = 20m/s.

In physics, we use the same formula for calculating speed and velocity. The only difference is that speed is a scalar quantity and as such has magnitude but no direction while velocity is a vector quantity and as such it has both magnitude and direction.

$Velocity = \frac{distance}{time}$

Therefore, the velocity is 20m/s due North.

6 0

3 years ago

A 2.00-kilogram object weighs 19.6 newtons on earth. if the acceleration due to gravity on mars is 3.71 meters per second2, what

Harrizon [31]

Recall that mass is the amount of matter present in a body. That means it's a property that is consistent regardless of the body's current location, gravity's pull on the body, etc.

Let's not confuse mass with weight (which is a force computed as Weight = mass x acceleration). Mass will remain constant and that means that whether the object is on Earth or on Mars, its mass remains the same. Thus, the object will still have 2.00 kg as mass on Mars.

Answers: 2.00 kilograms

4 0

3 years ago

Can anyone help me with this please​

Can anyone help me with this please