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3 years ago

Question 3.

Physics

1 answer:

morpeh [17]3 years ago

7 0

Answer: A. I,II and III

Explanation:

Let's describe the situation in a simplified way.

First remember, in ambient temperature, the candle is in solid form.

As you light the candle, the region of the candle near the flame suffers an increase in energy, caused by the heat of the flame. As you know, when we give enough heat to a solid, it will change of phase, from solid to liquid, and this is why the candle melts. Now, this change of phase is due to the heat of the flame, so when the liquid phase is away from the flame (because the flame went out, or because the liquid wax fell and now is far from the flame) the wax will cool down, and return to the solid phase.

Then we must have:

Presence of heat to go from solid to liquid.

Absence of heat to go from liquid to solid.

And we have a flame, then we must have presence of oxygen.

Then the correct option is:

A. I,II and III

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A projectile leaves the ground at an angle of 60° the horizontal.Its kinetic energy is E.Neglecting air resistance, find in term

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Answer:

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2 years ago

A train traveling at 27.5 accelerates to 42.4 m s over 75.0 s What is the displacement of the train in this time period A train

jarptica [38.1K]

Answer:

The displacement of the train in this time period is 2,616.86 m.

Explanation:

A Uniformly Varied Rectilinear Motion is Rectilinear because the mobile moves in a straight line, Uniformly because of there is a magnitude that remains constant (in this case the acceleration) and Varied because the speed varies, the final speed being different from the initial one.

In other words, a motion is uniformly varied rectilinear when the trajectory of the mobile is a straight line and its speed varies the same amount in each unit of time (the speed is constant and the acceleration is variable).

An independent equation of useful time in this type of movement is:

$vf^{2} =vi^{2} +2*a*d$ Expression A

where:

vf = final velocity
vi = initial velocity
a = acceleration
d = distance

The equation of velocity as a function of time in this type of movement is:

vf=vi + a*t

So the velocity can be calculated as: $a=\frac{vf-vi}{t}$

In this case:

vf=42.4 m/s
vi=27.5 m/s
t=75 s

Replacing in the definition of acceleration: $a=\frac{42.4 m/s-27.5 m/s}{75 s}$

a=0.199 m/s²

Now, replacing in expression A:

$(42.4 m/s)^{2} =(27.5 m/s)^{2} +2*(0.199 m/s^{2}) *d$

Solving:

$d= \frac{(42.4 m/s)^{2} - (27.5 m/s)^{2} }{2*(0.199 m/s^{2}) }$

d= 2,616.86 m

The displacement of the train in this time period is 2,616.86 m.

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3 years ago

2. A rod 14.0 cm long is uniformly charged and has a total charge of -22.0 μC. Determine the magnitude and direction of the net

Sloan [31]

Explanation:

It is given that,

Length of rod, l = 14 cm = 0.14 m

Total charge, $Q=-22\ \mu C=-22\times 10^{-6}\ C$

We need to find the magnitude and direction of the net electric field produced by the charged rod at a point 36.0 cm to the right of its center along the axis of the rod, z = 36 cm = 0.36 m

Electric field at the axis of rod is given by :

$E=\dfrac{\lambda}{2\pi \epsilon_o z}$