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Crazy boy [7]
3 years ago
10

A constant friction force of 21 N acts on a 63-kg skier for 25 s on level snow. What is the skier’s change in velocity?

Physics
1 answer:
erica [24]3 years ago
4 0
The skier’s change in velocity is 8.33.../8.4 m/s.
21/63= 0.33...
0.33...x 25 s = 8.33.../8.4 m/s
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330 g of water at 55°c are poured into an 855 g aluminum container with an initial temperature of 10°
Olenka [21]
The final temperature of the system is 32.5°
we know,  H = mcT 
where, H = Heat content of the body 
m = Mass,
c = Specific heat
T = Change in temperature
According to to the Principle of Calorimetry 

The net heat remains constant i.e. 
⇒ the heat given by water = heat accepted by the aluminum container.
⇒ 330 x 1 x (45 - T) = 855 x \frac{900}{4200} x (T - 10) 

⇒ 14,850 - 330T = 183.21T  - 1832 

⇒ - 513.21 T = - 16682

or T = 32.5°
3 0
3 years ago
Write about the similarities and differences between kinetic and potential energy. Include specific, real world example in your
lord [1]

Answer:

Energy is transformed from potential to kinetic and vice versa

Explanation:

The energy is transformed from mechanical to kinetic energy when the object changes its position with respect to a reference point, where it loses height but increases its speed. When the object is at maximum height with respect to a reference point, it will have its maximum potential energy value. When the object passes through the reference point it will have potential energy equal to zero, but this energy will become kinetic energy.

The most characteristic and real example is that of a pendulum at one end, as can be seen in the attached image.

When the pendulum is located at the top end, as shown in Figure 1, at that point the maximum potential energy will be held. Then the pendulum is released and when it passes through the reference point and its height is zero, with respect to that point, all potential energy will have become kinetic energy in the same way at this point the maximum speed of the pendulum will be set.

8 0
3 years ago
Vector vector b has x, y, and z components of 4.00, 4.00, and 2.00 units, respectively. calculate the magnitude of vector
Sav [38]
Good morning.

We see that \mathsf{\overset{\to}{b}} = \mathsf{(4.00, \ 4.00, \ 2.00)}

The magnitude(norm, to be precise) can be calculated the following way:

\star \ \boxed{\mathsf{\overset{\to}{a}=(x, y,z)\Rightarrow ||\overset{\to}{a}|| = \sqrt{x^2+y^2+z^2}}}


Now the calculus is trivial:

\mathsf{\|\overset{\to}{b} \| =\sqrt{4^2+4^2+2^2} =\sqrt{16+16+4}}\\ \\ \mathsf{\|\overset{\to}{b}\|=\sqrt{36}}\\ \\ \boxed{\mathsf{\|\overset{\to}{b}\| = 6.00 \ u}}
7 0
3 years ago
Suppose a photon with an energy of 1.60 eV strikes a piece of metal. If the electron that it hits loses 0.800 eV leaving the met
JulsSmile [24]

To solve this problem it is necessary to apply the concepts related to the change of Energy in photons and the conservation of energy.

From the theory we could consider that the energy change is subject to

\Delta E = E_0 -W_f

Where

E_0 =Initial Energy

W_f = Energy loses

Replacing we have that

\Delta E = 1.6-0.8

\Delta E = 0.8eV

Therefore the Kinetic energy of the electron once it has broken free of the metal surface is 0.8eV

7 0
3 years ago
The area under the curve of the net external force vs time graph is equal to __________ or ________.
Sophie [7]

Impulse delivered

or

Change in momentum.

7 0
3 years ago
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