Nancy is pushing her empty grocery cart at a rate of 1.8 m/s. 30 seconds later,

The diagram shows two vectors that point west and north. What is the magnitude of the resultant vector? 13 miles 17 miles 60 mil

Kipish [7]

Using the formula A squared plus B squared equals C squared, we can find the solution by substituting 5 for A and 12 for B.

By squaring 5, we get 25, and by squaring 12, we get 144. Adding these, we get 169. The square root of this is 13.

6 0

2 years ago

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You place a 500 g block of an unknown substance in an insulated container filled 2 kg of water. The block has an initial tempera

Nina [5.8K]

Answer:

3349J/kgC

Explanation:

Questions like these are properly handled having this fact in mind;

Heat loss = Heat gained

Quantity of heat = mcΔ∅

m = mass of subatance

c = specific heat capacity

Δ∅ = change in temperature

m₁c₁(∅₂-∅₁) = m₂c₂(∅₁-∅₃)

m₁ = mass of block = 500g = 0.5kg

c₁ = specific heat capacity of unknown substance

∅₂ = block initial temperature = 50oC

∅₁ = equilibrium temperature of block and water after mix= 25oC

m₂= mass of water = 2kg

c₂ = specific heat capacity of water = 4186J/kg C

∅₃ = intial temperature of water = 20oC

0.5c₁(50-25) = 2 x 4186(25-20)

And we can find c₁ which is the unknown specific heat capacity

c₁ = $\frac{2*4186*5}{0.5*25}$ = 3348.8J/kg C≅ 3349J/kg C

4 0

2 years ago

If period of the pendulum in preceding sample problem were 24s how tall would the tower be ?

frutty [35]

Answer:

So length of pendulum is 143.129 m

Explanation:

We have given period of simple pendulum is 2 sec

We have to find the length of simple pendulum

Let the length of pendulum is l

Acceleration due to gravity $g=9.8m/sec^2$ is

Time period is given by $T=2\pi \sqrt{\frac{l}{g}}$

So $24=2\times 3.14\times \sqrt{\frac{l}{9.8}}$

$\sqrt{\frac{l}{9.8}}=3.821$

Squaring both side

${\frac{l}{9.8}}=14.60$

l =143.129 m

So length of pendulum is 143.129 m

8 0

2 years ago

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4. Going back to the dog whistle in question 1, what is the minimum riding speed needed to be able to hear the whistle? Remember

jeyben [28]

Answer:

The minimum riding speed relative to the whistle (stationary) to be able to hear the sound at 21.0 kHz frequency is 15.7 m/s

Explanation:

The Doppler shift equation is given as follows;

$f' = \dfrac{v - v_o}{v + v_s} \times f$

Where:

f' = Required observed frequency = 20.0 kHz

f = Real frequency = 21.0 kHz

v = Sound wave velocity = 330 m/s

$v_o$ = Observer velocity = X m/s

$v_s$ = Source velocity = 0 m/s (Assuming the source is stationary)

Which gives;

$20 = \dfrac{330- v_o}{330+0} \times 21$

330 - $v_o$ = (20/21)*330

$v_o$ = 330 - (20/21)*330 = 15.7 m/s

The minimum riding speed relative to the whistle (stationary) to be able to hear the sound at 21.0 kHz frequency = 15.7 m/s.

8 0

2 years ago

If a metallic wire of cross sectional area 3.0 ´ 10-6 m2 carries a current of 6.0 A and has a mobile charge density of 4.24 ´ 10

elena-14-01-66 [18.8K]

Answer:

The drift velocity is $v_d=2.9\times 10^{-4}\ m/s.$

Explanation:

Given :

Area of metallic wire, $A = 3\times 10^{-6}\ m^2$ .

Current through wire , $I=6 \ A.$

Mobile charge density , $n=4.24\times 10^{28} \ carriers/m^3.$

Charge value , $e=1.6\times 10^{-19}\ C.$

We need to find drift velocity , $v_d.$

Now, we know :

$I=neAv_d$

Therefore, $v_d=\dfrac{I}{neA}$

Putting all given values in above equation we get,

$v_d=\dfrac{6}{4.24\times 10^{28}\times 1.6\times 10^{-19} \times 3 \times 10^{-6}}$

$v_d=2.9\times 10^{-4}\ m/s.$

Hence, this is the required solution.

8 0

2 years ago