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3 years ago

[01.02]

Physics

2 answers:

Illusion [34]3 years ago

8 0

Answer : speed

Explanation :

Speed is defined as the distance travelled per unit time. It is a scalar quantity.

Velocity is displacement covered per unit time. It is a vector quantity. This means it have both magnitude as well as direction.

When captain told the passengers that the plane is flying at 450 miles per hour, then this shows the speed of plane. He is not talking about the direction in which the plane is flying.

So, this information describes the speed of plane.

Correct option is (2).

julia-pushkina [17]3 years ago

6 0

That information describes the plane's speed.
If he had also told them what direction they were flying, then
they would have been able to put the two pieces of information
together, and they would know the plane's velocity.

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A basketball is shot. After the ball leaves the player's hand, in which direction does the ball accelerate?

azamat

Answer: Always accelerates in a downward direction

Explanation: Gravity is pulling the ball downward

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3 years ago

A sample contains 16 g of a radioactive isotope. how much radioactive

mafiozo [28]

After one half-life, 8 g of radioactive isotope will remain in the sample.

<h3>What is radioactivity?</h3>

The act of producing radiation spontaneously is known as radioactivity. This is accomplished by an unstable atomic nucleus that want to give up some energy in order to move to a more stable form.

The following formula is used to compute the number of half lives elapsed:

$\rm N=\frac{N_0}{2^n} \\\\ N=\frac{16}{2} \\\\ N= 8 \ gram$

Hence,8 gram of radioactive isotope remains in the sample after 1 half-life.

To learn more about the radioactivity, refer to the link;

brainly.com/question/1770619

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7 0

2 years ago

Read 2 more answers

1. An object in free fall will have an initial velocity equal to zero when: a. It is thrown vertically down

Ne4ueva [31]

Answer:

b. It is dropped

Explanation:

If the initial velocity is zero, the object move from rest. That happens if the object is dropped

6 0

3 years ago

A hockey puck has a coefficient of kinetic friction of μk = .35. If the puck feels a normal force (FN) of 5 N, what is the frict

alina1380 [7]

Answer:

The frictional force is $F_f = 1.75 \ N$

Explanation:

From the question we are told that

The coefficient of kinetic force is μk = 0.35

The normal force felt by the puck is $F_N = 5 \ N$

Generally the frictional force that acts on the puck is mathematically represented as

$F_f = \mu_k * F_N$

=> $F_f = 0.35 * 5$

=> $F_f = 1.75 \ N$

3 0

3 years ago

A confined aquifer with a porosity of 0.15 is 30 m thick. The potentiometric surface elevation at two observation wells 1000 m a

AlekseyPX

Answer:

Part (a) The flow rate per unit width of the aquifer is 1.0875 m³/day

Part (b) The specific discharge of the flow is 0.0363 m/day

Part (c) The average linear velocity of the flow is 0.242 m/day

Part (d) The time taken for a tracer to travel the distance between the observation wells is 4132.23 days = 99173.52 hours

Explanation:

Part (a) the flow rate per unit width of the aquifer

From Darcy's law;

$q = -Kb\frac{dh}{dl}$

where;

q is the flow rate

K is the permeability or conductivity of the aquifer = 25 m/day

b is the aquifer thickness

dh is the change in th vertical hight = 50.9m - 52.35m = -1.45 m

dl is the change in the horizontal hight = 1000 m

q = -(25*30)*(-1.45/1000)

q = 1.0875 m³/day

Part (b) the specific discharge of the flow

$V = \frac{Q}{A} = \frac{q}{b} = -K\frac{dh}{dl}\\\\V = -(25 m/d).(\frac{-1.45 m}{1000 m}) = 0.0363 m/day$

V = 0.0363 m/day

Part (c) the average linear velocity of the flow assuming steady unidirectional flow

Va = V/Φ

Φ is the porosity = 0.15

Va = 0.0363 / 0.15

Va = 0.242 m/day

Part (d) the time taken for a tracer to travel the distance between the observation wells

The distance between the two wells = 1000 m

average linear velocity = 0.242 m/day

Time = distance / speed

Time = (1000 m) / (0.242 m/day)

Time = 4132.23 days

$= 4132.23 days *\frac{24 .hrs}{1.day} = 99173.52, hours$

4 0

3 years ago