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2 years ago

The object was thrown vertically upwards at a speed of 30 m / s. How high does the body go?

Physics

1 answer:

valentina_108 [34]2 years ago

5 0

Answer:

4.9

Explanation:

Velocity half second before maximum height = Velocity half second after maximum height (Return journey)

For downward journey :

Initial velocity u=0 m/s

We have g=9.8 m/s

Time t= ½s

Thus velocity after half second v=u+gt

v=0+9.8× ½ =4.9m/s

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Consider a long rod of mass, m, and length, l, which is thin enough that its width can be ignored compared to its length. The ro

ehidna [41]

Answer:

Explanation:

The rod will act as pendulum for small oscillation .

Time period of oscillation

$T=2\pi\sqrt{\frac{l}{g} }$

angular frequency ω = 2π / T

= $\omega=\sqrt{\frac{g}{l} }$

b )

ω = 20( given )

velocity = ω r = ω l

Let the maximum angular displacement in terms of degree be θ .

1/2 m v ² = mgl ( 1 - cosθ ) ,

[ l-lcosθ is loss of height . we have applied law of conservation of mechanical energy .]

.5 ( ω l )² = gl( 1 - cos θ )

.5 ω² l = g ( 1 - cosθ )

1 - cosθ = .5 ω² l /g

cosθ = 1 - .5 ω² l /g

θ can be calculated , if value of l is given .

4 0

3 years ago

Superman can fly 600 miles in 2 in a half hours what is his speed

Digiron [165]

To solve for distance use the formula for distance d = st, or distance equals speed times time.

distance = speed x timeSpeed

so the answer is 240 miles per hour.

4 0

3 years ago

Distinguish between nonsampling error and sampling error. Choose the correct answer below.

kiruha [24]

Answer:

The correct answer is D.

Non-sampling error is the error that results from under-coverage, non-response bias, response bias, or data-entry errors. Sampling error is the error that results because a sample is being used to estimate information about a population.

Explanation:

Sampling error is related to the variation between the true values of the sample and the population. If occurred, it is always random depending upon the sample chosen.

Non-sampling error can be random as well as non-random. Non-sampling error can occur irrespective of the sample chosen. It is related to the inappropriate analysis of the data.

5 0

3 years ago

A 75 kV x-ray machine gives an exposure of 200 mR for a 0.2-sec chest x-ray exam.

pashok25 [27]

Explanation:

Given that,

Potential = 75 kV

Exposure = 200 mR

Time = 0.2 sec

We need to calculate the x-ray fluence during this chest x-ray exam

Using formula of fluence

$x-ray\ fluence=exposure\times time$

Put the value into the formula

$x-ray\ fluence=200\times0.2$

$x-ray\ fluence=40\ mRs$

We need to calculate the energy fluence

Using formula of energy fluence

$E_{f}=40\times10^{-3}\times75\times10^{3}$

$E_{f} = 3000\ J$

We need to calculate dose -equivalent delivered to the bone, muscle, and fat

Using formula of dose

$D=\dfrac{E}{t}$

Where, D = dose

E = energy

t = time

Put the value into the formula

$D=\dfrac{3000}{0.2}$

$D=15.0\ kJ$

Hence, This is the required solution.

7 0

3 years ago

You have arrived at the scene of a two car accident. You know the following pieces of information:

Pani-rosa [81]

The initial velocity of car 1 is 20 m/s to the right

The initial velocity of car 2 is zero

The final velocity of car 2 is 10 m/s to the right

Explanation:

We can solve the problem by using the law of conservation of momentum: the total momentum of the system must be conserved before and after the collision.

Therefore, we can write:

$p_i = p_f\\m_1 u_1 + m_2 u_2 = m_1 v_1 + m_2 v_2$