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Anettt [7]
3 years ago
6

An acorn falls from a tree. Its velocity just before it hits the ground is 28.2 m/s, downward. (acceleration of gravity is 9.81m

/s2). what is the acorn velocity at 1.4 s?
Physics
1 answer:
ss7ja [257]3 years ago
7 0

Answer:

12.74 ms^-1 download

Explanation:

v=28.2, a=9.81

start from rest u=0

v=u+at=0+(9.81)t=28.2

t=2.875...

it reach 1.4 second before hitting the ground:

t=1.4, u=0, a=9.81

v=u+at=0+(9.81)(1.4)=12.74

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A projectile is fired over level ground with an initial velocity that has a vertical component of 20 m/s and a horizontal compon
Anettt [7]
First of all, let's write the equation of motions on both horizontal (x) and vertical (y) axis. It's a uniform motion on the x-axis, with constant speed v_x=30 m/s, and an accelerated motion on the y-axis, with initial speed v_y=20 m/s and acceleration g=9.81 m/s^2:
S_x(t)=v_xt
S_y(t)=v_y t- \frac{1}{2} gt^2
where the negative sign in front of g means the acceleration points towards negative direction of y-axis (downward).

To find the distance from the landing point, we should find first the time at which the projectile hits the ground. This can be found by requiring
S_y(t)=0
Therefore:
v_y t -  \frac{1}{2}gt^2=0
which has two solutions:
t=0 is the time of the beginning of the motion,
t= \frac{2 v_y}{g} = \frac{2\cdot 20 m/s}{9.81 m/s^2}=4.08 s is the time at which the projectile hits the ground.

Now, we can find the distance covered on the horizontal axis during this time, and this is the distance from launching to landing point:
S_x(4.08 s)=v_x t=(30 m/s)(4.08 s)=122.4 m
4 0
3 years ago
Plz help........................
hoa [83]

Answer:

The correct wording is

  1. Pressure increases with the depth of the fluid.
  2. A plane's engines produce thrust to push the plane forward.
  3. A fluid can be a liquid or a gas.
  4. A hydraulic device uses Pascal's principle to lift or move objects.
  5. lift is the upward force exerted on objects by fluids.

Explanation:

1. As you go deeper into a fluid,<em> there is more of it on top of you; </em>therefore, the pressure excreted on you is greater.

2. A plane's engines pushes the air in opposite direction, which according to newton's third law, produces necessary force to move the plane forward.

3.  <em>A fluid has no fixed shape,</em> and it deforms under the influence of external forces applied—liquid and gases fit into this definition.

4. Pascal's principle <em>says that pressure applied on one region of the fluid must equal pressure transmitted to another region of the same fluid</em>. This principle is used in a hydraulic device to exert forces on fluids to lift objects that would otherwise be difficult to move.

5. By definition, the upward force exerted by the fluids on objects is the lift.

7 0
3 years ago
Each of the rods depicted below were machined from same stock metal. They were originally machined to be the same length, but th
Shkiper50 [21]

The force required to extend a rod increases as the cross sectional area

increases.

The rod that experiences the largest force is <u>rod B</u>

Reason:

The elongation of a rod by the application of a force is given by the

following formula;

\Delta L = \dfrac{F \cdot L}{A \cdot E}

From the above equation, we have that the elongation is inversely

proportional to the cross sectional area, such that the extension of a rod by

a given force reduces as the cross sectional area of the rod increases.

Therefore, the force required to extend the length of a rod by a specific

amount increases as the cross sectional area of the rod increases,

indicating that the rod with the largest cross sectional area require the

most force and therefore, experiences the largest force.

The rod that experiences the largest force is the rod with the largest cross

sectional area, which is <u>rod B</u>

Learn more here:

brainly.com/question/12937199

4 0
2 years ago
A record player has a velocity of 33.33 RPM. How fast is the record spinning in m/s at a distance of 0.085 m from the center?
anygoal [31]

Answer:

A record player has a velocity of 33.33 RPM. How fast is the record spinning in m/s at a distance of 0.085 m from the center? [0.297 m/s] 6. A merry-go-round a.k.a “the spinny thing” is rotating at 15 RPM, and has a radius of 1.75 m A.

5 0
3 years ago
Read 2 more answers
If the particles of an object have more kinetic energy than the particles of an object, what must be true?
son4ous [18]

If the objects comprise a gas, then the first object contains more
thermal energy (heat) than the second object.

If the objects are solid, then you can't draw any conclusion unless
both objects have the same total mass. If that's the case, then the
first object must be moving faster than the second one.


7 0
3 years ago
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