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4 years ago

A golf pro has 2100 J of kinetic energy and swings his driver which weighs .75 kg. What is the speed of his swing?

Chemistry

2 answers:

jeka57 [31]4 years ago

8 0

Answer : The correct answer is 74.83 m/s .

The kinetic energy is energy possessed by any mass which is moving or have some speed . It is product of mass and velocity . It is expressed as :

$KE = \frac{1}{2} * m* v^2$

Where KE = kinetic energy in J or $kg\frac{m^2}{s^2}$ m = mass in Kg v = speed in m/s²

Unit of KE is Joules (J) .

Givne : KE = 2100 J mass = 0.75 kg v = ?

Plugging value in KE formula =>

$2100 J = \frac{1}{2} * 0.75 Kg * v^2$

$2100 J = 0.375 Kg * v^2$

Dividing both side by 0.375 kg =>

$\frac{2100 J}{0.375 Kg} = \frac{0.375 Kg}{0.375 Kg } * v^2$

$v^2 = 5600 \frac{m^2}{s^2}$

$v= 74.83 \frac{m}{s}$

Kazeer [188]4 years ago

7 0

The speed of his swing is 56 m/s

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Attempt 3 During an experiment, a student adds 2.90 g CaO 2.90 g CaO to 400.0 mL 400.0 mL of 1.500 M HCl 1.500 M HCl . The stude

kondor19780726 [428]

Answer:

Explanation:

Equation of the reaction:

CaO(s) + 2H+(aq) -----> Ca2+(aq) + H2O(g)

The ∆Hrxn would be for one mole of CaO reacted or 2 moles of H+, whichever is the limiting reactant.

Number of moles = mass ÷ molar mass

Molar mass of CaO = 40 + 16

= 56 g/mol

moles of CaO = 2.90/56

= 0.0518 mol

Number of moles = concentration × volume

moles of HCl = 400 × 10^-3 × 1.500 = 0.6 moles

Moles of HCl = moles of H+

From the equation, 1 mole of CaO reacted with 2 moles of H+ to give 1 mole of water.

To find the limiting reagent,

0.6 mole of H+/2 moles of H+ × 1 mole of CaO

= 0.3 moles of CaO(> 0.0518 moles)

So, CaO is limiting reactant.

∆H = m × Cp × ∆T

m = density × volume

= 400 × 1

= 400 g

Cp = 4.184 J/g-ºC

∆T = +6 ºC

∆H = 400 × 4.184 × 6

= 10041.6 J

Since the reaction is exothermic,

∆Hrxn = -∆H/mol(CaO)

= -10041.6/0.0518

= -193853 J

= -193.9 kJ/mol.

3 0

3 years ago

How much heat (in kJ) would need to be removed to cool 150.3 g of water from 25.60°C to -10.70°C?

olga_2 [115]

Answer:

Q = -22.9 kJ

Explanation:

Given that,

Mass of water, m = 150.3 g

Water gets cool from 25.60°C to -10.70°C.

The specific heat of water, c = 4.2 J/g°C

The formula for heat needed is given by :

$Q=mc\Delta T\\\\Q=150.3\times 4.2 \times (-10.7-25.6)\\\\Q=-22914.738\\\\or\\\\Q=22.9\ kJ$

So, 22.9 kJ of heat is needed to be removed to cool.

8 0

3 years ago

3. Is the following statement a fact, opinion or theory? Why?

Nesterboy [21]

This is an opinion. The person believes that eggs are better than cereal for breakfast. When someone else might disagree with that and say that cereal is better then eggs for breakfast.

7 0

3 years ago

At STP, adding salt to a 200 mL sample of water produces a saturated 1.7 M solution. How many grams of salt (NaCl) must be added

Illusion [34]

Answer:

$m_{NaCl}=19.9gNaCl$

Explanation:

Hello!

In this case, since the formula for the calculation of molarity is:

$M=\frac{n}{V}$

Whereas we can compute the moles of the solute as shown below, making sure the volume is in liters:

$n=M*V$

Thus, by plugging in we obtain:

$n=0.200L*1.70mol/L=0.170molNaCl$

Next, since the molar mass of NaCl is 58.44 g/mol, we obtain the following mass:

$m_{NaCl}=0.170molNaCl*\frac{58.44gNaCl}{1molNaCl}\\\\m_{NaCl}=19.9gNaCl$

Best regards!

3 0

3 years ago

9. A student observed the following reaction:

Gelneren [198K]

Answer:

The substance that remained on the filter paper is Al(OH).

Explanation:

Filter paper is the substance that is used in laboratory to separate the solid objects. It doesn't filter aqueous and gaseous products.
So in our experiment the product formed is aluminum hydroxide Al(OH) and sodium chloride (NaCl).
Between two products, sodium chloride is in aqueous form as indicated in the question. So it wont remain in the filter paper.

Hence aluminum hydroxide being only solid product remains on the filter paper.

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3 years ago