The table below shows the difference between the average temperatures in April and October in four locations.

An airplane, starting from rest, moves down the runway at constant acceleration for 18 s and then takes off at a speed of 60 m/s

ruslelena [56]

Answer:

a =3.33 m/s²

Explanation:

given,

initial speed of Plane, u = 0 m/s

final speed of plane, v = 60 m/s

time of the acceleration, t = 18 s

average acceleration of the plane, a = ?

average acceleration is equal to change in velocity per unit time.

$a = \dfrac{v - u}{t}$

$a = \dfrac{60 - 0}{18}$

$a = \dfrac{60}{18}$

a =3.33 m/s²

Hence, average acceleration of the plane is equal to a =3.33 m/s²

4 0

3 years ago

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If oxygen and steel wool are combined is it a physical change or chemical change?

Anon25 [30]

Answer:

I think it would be a chemical change.

Explanation:

Because a physical would be like crushing it or something along that line.

4 0

3 years ago

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A boy standing throws a penny horizontally at 7.25 m/s out of the window of his apparent buliding. If the window is 10.0 m above

Ksivusya [100]

Answer:

Explanation:

This is a 2D problem (parabolic) so we have to think that way. We have to split up the problem into its 2 dimensions to solve it. Think "y-stuff" and "x-stuff".

In the y-stuff category:

v₀ = 0 (initial upwards velocity is 0 since we are told the penny is thrown horizontally)

Δx = -10.0 m (this displacement is negative because the penny lands 10.0 m below the point from which it was thrown)

a = -9.8 m/s/s

t = ? (we need to find the time in this dimension so we can use it in the x dimension to find the displacement, our unknown)

In the "x-stuff" category:

v₀ = 7.25 m/s (this is given)

Δx = ???

a = 0 (acceleration in this dimension is ALWAYS 0)

t = (we will solve for this in the y-dimension and plug it in here).

In the y dimension:

Δx = v₀t + $\frac{1}{2}at^2$ and plugging in from the y-dimension info:

$-10.0=0t+\frac{1}{2}(-9.8)t^2$ which simplifies to

$-10.0=-4.9t^2$ so

$t=\sqrt{\frac{-10.0}{-4.9} }$ which, to 2 significant digits is

t = 1.4 seconds

Now we will do the same in the x-dimension, using t = 1.4:

Δx = v₀t + $\frac{1}{2}at^2$ and filling in the x-stuff:

Δx = $7.25(1.4)+\frac{1}{2}(0)(1.4)^2$ Notice that the stuff after the + sign goes to 0 cuz of the multiplication of 0, so what we are left with is another form of the d = rt equation: