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4 years ago

11

A football field is about 100 m long. If it takes a person 20 seconds to run its length, how fast (what speed) were they running

?

1 answer:

leonid [27]4 years ago

3 0

Answer:

Speed, v = 5 m/s

Explanation:

We have,

The length of the football field, l = 100 m

A person takes 20 seconds to run its length.

It is required to find the speed of the person with which he should run. The distance covered divided by time taken is called its velocity.

$v=\dfrac{d}{t}\\\\v=\dfrac{100\ m}{20\ s}\\\\v=5\ m/s$

So, the speed of the person is 5 m/s.

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To get an idea of the size of magnetic fields at the atomic level, consider the magnitude of the magnetic field due to the elect

artcher [175]

Answer:

The magnetic field is 14.08 T.

Explanation:

Given that,

Speed of electron $v=2.2\times10^{6}\ m/s$

Distance $d =0.5\times10^{-10}\ m$

Suppose we need to find the magnetic field at the location of the proton

We need to calculate the magnetic field

Using formula of magnetic field

$B = \dfrac{\mu_{0}I}{2r}$ ....(I)

Using formula of current

$I=\dfrac{q}{T}$

Using formula of time

$T= \dfrac{2\pi r}{v}$

Put the value of current and time in equation (I)

$B=\dfrac{\mu \times q\times v}{2\pi r\times2r}$

Put the value into the formula

$B=\dfrac{4\pi\times10^{-7}\times1.6\times10^{-19}\times2.2\times10^{6}}{4\pi\times(0.5\times10^{-10})^2}$

$B=14.08\ T$

Hence, The magnetic field is 14.08 T.

3 0

3 years ago

If an object is dropped from a tall building and hits the ground 3.0 s. later, what is the magnitude of the object's displacemen

marin [14]

Find the velocity of the object after one second.

v = vo + at

v = (0 m/s) + (9.8 m/s^2)(1 s)

v = 9.8 m/s

Now, using that, you can find the displacement in that one second between 1 and 2.

d = vot + (1/2)at^2

d = (9.8 m/s)(1 s) + (1/2)(9.8 m/s^2)(1 s)^2

d = 14.7 m

5 0

3 years ago

Read 2 more answers

A firecracker breaks up into three pieces, one of which has a mass of 200 g and flies off along the x-axis with a speed of 82.0

Mamont248 [21]

Answer:

$|P_3|=21.242m/s$

Explanation:

From the question we are told that:

Mass $m=200g=0.2$

Speed $v=82.0m/s$

Mass $M_2=300g=0.3kg$

Speed $V_2=45.0m/s$

Generally the equation for Magnitude of the Third piece is mathematically given by

$P_1+P_2+P_3=0$

$|P_3|=|P_1+P_2|$

Where

$P_1=m_1v_1$

$P_1=0.2*82$

$P_1=16.4kgm/s$

And

$P_2=0.3*45$

$P_2=13.5kgm/s$

Therefore

$|P_3|=\sqrt{16.4^2+13.5^2}$

$|P_3|=21.242m/s$

8 0

3 years ago

A badminton player shuffles his shoes in resins explain the scientific reason behind this

Kobotan [32]

Answer:

To avoid slipping while playing badminton or to increase friction between the shoes and the badminton court or to enhance the grip.

Explanation:

As the question is general so I will try answer it generally.

As badminton court is usually slippery and flat with no or very little friction and while playing badminton, players have to move very fast from place to place.

So, in order to effectively move faster to take the difficult shots with accuracy badminton players increase the friction between their shoes and the badminton court by shuffling resin to their shoes. It helps to enhance the grip.

4 0

3 years ago

How many electrons are in the third energy level?

sp2606 [1]

7 is the answer i think

8 0

3 years ago