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3 years ago

A train traveled 350km in 2.5h. what was the average speed of the train?

Physics

2 answers:

Salsk061 [2.6K]3 years ago

4 0

Answer:

The answer is 140km/h

Step by step Explanation:

Velocity is the variation in the position of an object in a given time, that is, it is the distance traveled by an object in a unit of time.

The velocity is expressed by the formula $v = \frac{d}{t}$

If we replace the values given in the velocity formula we will have:

$v = \frac{350km}{2.5h} \\v = 140 km/h$

MaRussiya [10]3 years ago

3 0

Speed equals distance divided by time, so 350 divided by 2.5 equals 140 kilometers per hour.

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A worker at the top of a 588-m-tall television transmitting tower accidentally drops a heavy tool. If air resistance is negligib

liq [111]

The final velocity of the tool is 107.4 m/s

Explanation:

We can solve this problem by using the principle of conservation of energy.

In fact, if air resistance is negligible, the total mechanical energy of the tool is conserved during the fall, so we can write:

$K_i + U_i = K_f + U_f$

where

$K_i = 0$ is the kinetic energy of the tool at the top (zero since it is at rest)

$U_i = mgh$ is the gravitational potential energy of the tool at the top, where

m is the mass of the tool

g is the acceleration of gravity

h is the heigth of the tool

$K_f = \frac{1}{2}mv^2$ is the kinetic energy of the tool just before hitting the ground, where

v is the final speed of the tool

$U_f = 0$ is the gravitational potential energy of the tool at the bottom (zero since the height is zero)

Re-arranging the equation,

$mgh=\frac{1}{2}mv^2$

where we have

$g=9.8 m/s^2\\h=588 m$

And solving for v,

$v=\sqrt{2gh}=\sqrt{2(9.8)(588)}=107.4 m/s$

Learn more about kinetic energy and potential energy:

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3 years ago

A student uses an audio oscillator of adjustable frequency to measure the depth of a water well. The student reports hearing two

katrin [286]

Answer:

a) L = 33.369 m , b) 21

Explanation:

The analysis of the ocean depth can be performed assuming that at the bottom of the ocean there is a node and the surface must have a belly, so the expression for resonance is

λ = 4 L / n

n = 1, 3, 5, ...

The speed of the wave is

v = λ f

v = 4L / n f

L = n v / 4f

Let's write the expression for the two frequencies

L = n₁ 343/4 53.95

L = n₁ 1,589

L = n₂ 343/4 59

L = n₂ 1.4539

Let's solve the two equations

n₁ 1,589 = n₂ 1,459

n₁ / n₂ = 1.4539 / 1.589

n₁ / n2 = 0.91498

Since the two frequencies are very close the whole numbers must be of consecutive resonances, let's test what values give this value

n₁ n₂ n₁ / n₂

1 3 0.3

3 5 0.6

5 7 0.7

7 9 0.77

9 11 0.8

17 19 0.89

19 21 0.905

21 23 0.913

23 25 0.92

Therefore the relation of the nodes is n₁ = 21 and n₂ = 23

Let's calculate

L = n₁ 1,589

L = 21 1,589

L = 33.369 m

b) the number of node and nodes is equal therefore there are 21 antinode

4 0

3 years ago

The amount of air resistance acting on an object depends on the objects

alexandr402 [8]

Answer:

Shape of the object

Explanation:

This depends on the shape of the object. For a spherical object, a unitless value of 0.47 is typical. The magnitude of the velocity squared. The faster you go, the greater the air resistance force

7 0

2 years ago

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself.There is no one ar

Ira Lisetskai [31]

Answer: magnitude of applied force is FA = mg + F

Where F is the resultant force downward that the rope moves with

Explanation:

Force downwards F is,

F = FA - T

T is the upwards tension force on the rope

FA is the actual applied force in pulling the rope down.

Therefore, T = FA - F .....equ. (1)

For the box to move up with force ma ( it's mass times its acceleration upwards) upwards tension on the roap must exceed its own weight mg ( it's mass times acceleration due to gravity 9.8m/s^2)

Therefore, ma = T - mg

T = ma + mg ..... equ. (2)

Equating equ. 1 and 2

T = FA - F = ma + mg

Therefore FA = ma + mg + F

But at constant velocity a = 0

Magnitude of applied force becomes

FA = mg + F

See image below

5 0

3 years ago

How much work is done by 0.070 m3 of gas, when the volume remains constant with pressure of 63 x 105 Pa?

ICE Princess25 [194]

Answer:

W = 0 J

Explanation:

The amount of work done by gas at constant pressure is given by the following formula:

$W = P\Delta V$

where,

W = Work done by the gas

P = Pressure of the gas

ΔV = Change in the volume of the gas

Since the volume of the gas is constant. Therefore, there is no change in the volume of the gas:

$W = P(0\ m^3)\\$

5 0

2 years ago