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sergij07 [2.7K]

3 years ago

13

If a golf ball is dropped from the thirteenth floor of a building, ignoring air resistance, after falling for 7.00 seconds the s

peed of the ball will be?

1 answer:

PIT_PIT [208]3 years ago

6 0

Explanation:

We know that

V = U + at

Here, u is 0 and a is 9.8 which is acceleration due to gravity.

Thus,

V = 9.8 *7

V = 68.6 m/s

You might be interested in

A flat coil having 160 turns, each with an area of 0.20 m 2, is placed with the plane of its area perpendicular to a magnetic fi

S_A_V [24]

Answer:

10.2 Watt

Explanation:

$N$ = number of turns in flat coil = 160

$A$ = area = 0.20 m²

B₀= initial magnetic field = 0.40 T

$B$ = final magnetic field = - 0.40 T

Change in magnetic field is given as

ΔB = B - B₀ = - 0.40 - 0.40 = - 0.80 T

$t$ = time taken for the magnetic field to change = 2.0 s

Induced emf is given as

$E = \frac{- N A \Delta B}{t}$

$E = \frac{- (160) (0.20) (- 0.80)}{2}$

$E$ = 12.8 volts

$R$ = Resistance of the coil = 16 Ω

Power is given as

$P = \frac{E^{2}}{R}$

$P = \frac{(12.8)^{2}}{16}$

$P$ = 10.2 Watt

6 0

3 years ago

The volume occupied by a sample of gas is 480 mL when the pressure is 115 kPa.What pressure must be applied to the gas to make i

balandron [24]

Answer:

The answer is

<h2>84.9 kPa</h2>

Explanation:

Using Boyle's law to find the final pressure

That's

$P_1V_1 = P_2V_2$

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

Since we are finding the final pressure

$P_2 = \frac{P_1V_1}{V_2}$

From the question

P1 = 115 kPa

V1 = 480 mL

V2 = 650 ml

So we have

$P_2 = \frac{115000 \times 480}{650} = \frac{55200000}{650} \\ = 84923.076923...$

We have the final answer as

<h3>84.9 kPa</h3>

Hope this helps you

7 0

3 years ago

Which of these ionic compounds have polyatomic ions? Check all that apply.

Taya2010 [7]

Answer:

CaCO₃ and
NaOH.

Explanation:

Polyatomic ions are ions that contain more than one atom in each one of the ions.

Ionic compounds are made of cations (positive ions) and anions (negative ion). By convention, the cation is written before the anion.

List the ions in each compound:

<h3>CaCO₃</h3>

Cation: $\rm Ca^{2+}$ ,

Anion: $\rm {CO_3}^{2-}$ .

$\rm Ca^{2+}$ is a monatomic ion for it contains only one atom in each ion.

$\rm {CO_3}^{2-}$ is a polyatomic ion for it contains four atoms (one C atom and three O atoms) in each ion.

<h3>NaF</h3>

Cation: $\rm Na^{+}$ ,

Anion: $\rm F^{-}$ .

Both $\rm Na^{+}$ and $\rm F^{-}$ are monatomic for they contain only one atom in each ion.

<h3>FeO</h3>

Cation: $\rm Fe^{2+}$ ,

Anion: $\rm {O}^{2-}$ .

Both $\rm Fe^{2+}$ and $\rm O^{2-}$ are monatomic for they contain only one atom in each ion.

<h3>CaCl₂</h3>

Cation: $\rm Ca^{2+}$ ,

Anion: $\rm {Cl}^{-}$ .

Both $\rm Ca^{2+}$ and $\rm Cl^{-}$ are monatomic for they contain only one atom in each ion.

<h3>NaOH</h3>

Cation: $\rm Na^{+}$ ,

Anion: $\rm {OH}^{-}$ .

$\rm Na^{+}$ is a monatomic ion for it contains only one atom in each ion.

$\rm {OH}^{-}$ is a polyatomic ion for it contains two atoms (one O atom and one H atom) in each ion.

5 0

3 years ago

Read 2 more answers

Place the following into scientific notation...(.000635)<br> *

AleksAgata [21]

6.35x10^-4 OR 6.3x10-4 (if only one decimal number is allowed)

6 0

3 years ago

A pendulum takes 6.0 seconds to swing through 5 complete cycles. What is the period of the pendulum?

photoshop1234 [79]

When you look at this, you might not be sure which way to divide ...
Should you divide 6 by 5 or 5 by 6 ?

Here's a case where you can use your units to decide.

The question wants to know the 'period'. That's a length of time,
so the answer needs to have units of time.

If you divide 'cycles' be 'time', you'll get 'cycles/second'.
That's Hz. It's frequency, not time.

If you divide 'time' by 'cycles', you'll get 'seconds/cycle'.
That's time, and it's exactly the definition of 'period'.

Period = (6 seconds) / (5 cycles)

= (6 / 5) seconds/cycle

= 1.2 seconds

6 0

3 years ago