A train has a constant velocity of 2 m/s. east what is the magnitude of the horizontal acceleration of the trian?

the sole of a tennis shoe has a surface area of 0.0290 m^2. if it is worn by a 65.0 kg person, what pressure does the shoe exert

AURORKA [14]

Answer: 21965.517 Pa

Explanation:

Pressure $P$ is the force $F$ exerted by a gas, a liquid or a solid on a surface (or area) $A$ , its unit is Pascal $Pa$ which is equal to $N/m^{2}$ and its formula is:

$P=\frac{F}{A}$ (1)

In this case we have the surface of a sole of a tennis shoe:

$A=0.0290 m^{2}$ (2)

And the mass $m$ of the person who wears it:

$m=65 kg$

On the other hand, we know the weight is the force $F$ the Earth exerts on people and objects due gravity $g$ :

$F=m.g=(65 kg)(9.8m/^{2})$

$F=637N$ (3)

Substituting (2) and (3) in (1):

$P=\frac{637N}{0.0290 m^{2}}$ (4)

Finally:

$P=21965.517 Pa$ This is the pressure the shoe exert on the ground

5 0

2 years ago

A baseball is hit almost straight up into the air with a speed of 26 m/s . Estimate how high it goes.

Natalka [10]

Answer:

The maximum height of the ball is 34.5 m.

The ball is 5.31 s in the air.

Explanation:

Hi there!

The equations for the height and velocity of the baseball that is hit straight up are as follows:

y = y0 + v0 · t + 1/2 · g · t²

v = v0 + g · t

Where:

y = height of the baseball at time t.

y0 = initial height.

v0 = initial velocity.

t = time.

g = acceleration due to gravity (-9.8 m/s² considering the upward direction as positive).

v = velocity at time t.

If we place the origin of the frame of reference at the place where the baseball is hit, then, y0 = 0.

To calculate how high it goes, we have to obtain the time at which the ball is at maximum height. At that point, the velocity is 0. Then using the equation of velocity:

v = v0 + g · t

0 = 26 m/s - 9.8 m/s² · t

-26 m/s / -9.8 m/s² = t

t = 2.65 s

The height at that time will be the maximum height:

y = y0 + v0 · t + 1/2 · g · t² (y0 = 0)

y = 26 m/s · 2.65 s - 1/2 · 9.8 m/s² · (2.65 s)²

y = 34.5 m

The maximum height of the ball is 34.5 m

If it takes the ball 2.65 s to reach the maximum height it will take another 2.65 s to return to the initial position. Then, the time it will be in the air is (2.65 s + 2.65 s) 5.30 s. However, let´s calculate the time it takes the ball to reach the initial position using the equation for height.

At the initial position y = 0. Then:

y = y0 + v0 · t + 1/2 · g · t² (y0 = 0)

0 = 26 m/s · t - 1/2 · 9.8 m/s² · t²

0 = t (26 m/s - 1/2 · 9.8 m/s² · t) (t = 0 when the ball is hit)

0 = 26 m/s - 1/2 · 9.8 m/s² · t

-26 / -4.9 m/s² = t

t = 5.31 s ( the difference with the 5.30 s obtained above is due to rounding the time to 2.65 s).

The ball is 5.31 s in the air.

Have a nice day!

5 0

3 years ago

explain y it is easier to loosen a tight but using a spanner with along handle than with a short handle

8090 [49]

Answer:

This is because using a long handled requires less force to the center of gravity and makes it easier to rotate than a short handled spanner

3 0

2 years ago

The multiple reflection of a single sound wave is a/an

ANTONII [103]

A single reflection, like shouting at the side of a mountain and hearing
your voice come back to you, is an 'echo'.

Multiple reflection, like clapping your hands once inside a large room,
is 'reverberation'.

8 0

3 years ago

A square piece of tin has 12 inches on a side. An open box is formed by cutting out equal square pieces at the corners and bendi

Citrus2011 [14]

Answer:

Explanation:

Given a square Piece whose side is 12 inches

Now square pieces are cut from each corner to make it a open box

Suppose x is the length of square piece at each corner

then

base square has a length of $12-2x$