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2 years ago

Roger drives his car at a constant speed of 80 km/hr. How far can he travel in 2 hrs. and 30 minutes?

Physics

1 answer:

bonufazy [111]2 years ago

6 0

Answer:

200 km/hr

Explanation:

Since he goes 80km per hour, multiply this by 2.5 or two and a half hours.

80 x 2.5 = 200 km/hr.

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A world-class tennis player can serve a tennis ball at 130 mi/h mi/h (about 58 m/s m/s ). The length of a tennis court is 78 ft

riadik2000 [5.3K]

Answer:

The time taken is $t = 0.4103 \ s$

Explanation:

From the question we are told that

The speed is $v = 130 \ mi/h = 58 \ m/s$

The length of the tennis court $l = 78 \ ft = \frac{78}{3.281}= 23.8 \ m$

Generally the time taken is mathematically represented as

$t = \frac{ 23.8}{ 58}$

=> $t = 0.4103 \ s$

8 0

3 years ago

A uniform rod of mass 3.30×10−2 kg and length 0.450 m rotates in a horizontal plane about a fixed axis through its center and pe

Alex73 [517]

(a) 2.75 rev/min

The moment of inertia of the rod rotating about its center is:

$I_R=\frac{1}{12}ML^2$

where

$M=3.30\cdot 10^{-2} kg$ is its mass

L = 0.450 m is its length

Substituting,

$I_R=\frac{1}{12}(3.30\cdot 10^{-2})(0.450)^2=5.57\cdot 10^{-4} kg m^2$

The moment of inertia of the two rings at the beginning is

$I_r = 2mr^2$

where

m = 0.200 kg is the mass of each ring

$r=5.20\cdot 10^{-2} m$ is their distance from the center of the rod

Substituting,

$I_r=2(0.200)(5.20\cdot 10^{-2})^2=1.08\cdot 10^{-3} kg m^2$

So the total moment of inertia at the beginning is

$I_1=I_R+I_r = 5.57\cdot 10^{-4}+1.08\cdot 10^{-3}=1.64\cdot 10^{-3}kg m^2$

The initial angular velocity of the system is

$\omega_1 = 35.0 rev/min$

The angular momentum must be conserved, so we can write:

$L=I_1 \omega_1 = I_2 \omega_2$ (1)

where $I_2$ is the moment of inertia when the rings reach the end of the rod; in this case, the distance of the ring from the center is

$r=\frac{0.450 m}{2}=0.225 m$

so the moment of inertia of the rings is

$I_r=2(0.200)(0.225)^2=0.0203 kg m^2$

and the total moment of inertia is

$I_2 = I_R + I_r =5.57\cdot 10^{-4} + 0.0203 = 0.0209 kg m^2$

Substituting into (1), we find the final angular speed:

$\omega_2 = \frac{I_1 \omega_1}{I_2}=\frac{(1.64\cdot 10^{-3})(35.0)}{0.0209}=2.75 rev/min$

(b) 103.0 rev/min

When the rings leave the rod, the total moment of inertia is just equal to the moment of inertia of the rod, so:

$I_2 = I_R = 5.57\cdot 10^{-4}kg m^2$

So using again equation of conservation of the angular momentum:

$L=I_1 \omega_1 = I_2 \omega_2$

We find the new final angular speed:

$\omega_2 = \frac{I_1 \omega_1}{I_2}=\frac{(1.64\cdot 10^{-3})(35.0)}{5.57\cdot 10^{-4}}=103.0 rev/min$

7 0

3 years ago

20 POINTS WILL BE MARK BRAINLIEST<br><br> ATTACHED BELOW GAS LAW WORKSHEET

german

Explanation:

I will do two of each as examples.

Boyle's law says that at constant temperature, the product of the initial pressure and volume equals the product of the final pressure and volume.

1. P₁ V₁ = P₂ V₂

(1.5 atm) (10.0 L) = (0.75 atm) V

V = 20.0 L

2. P₁ V₁ = P₂ V₂

(100.0 kPa) (500.0 mL) = P (1,000.0 mL)

P = 50.0 kPa

Charles' law says that at constant pressure, the quotient of the initial volume and temperature equals the quotient of the final volume and temperature.

6. V₁ / T₁ = V₂ / T₂

(10.0 L) / (1500 K) = V / (750 K)

V = 5.0 L

7. V₁ / T₁ = V₂ / T₂

(500.0 mL) / (100 K) = (1000.0 mL) / T

T = 200 K

7 0

3 years ago

A 0.12 g honeybee acquires a charge of +24pC while flying. The earth's electric field near the surface is typically 100 N/C, dow

shusha [124]

Answer:

150000000

$\dfrac{F_e}{F_g}=0.00000203873598369$

49050000 N/C

Explanation:

q = Charge = 24 pC

m = Mass of honeybee = 0.12 g

E = Electric field = 100 N/C

g = Acceleration due to gravity = 9.81 m/s²

$1\ C=6.25\times 10^{18}\ electrons$

Number electrons is

$n=24\times 10^{-12}\times 6.25\times 10^{18}\\\Rightarrow n=150000000$

The number of electrons added or removed was 150000000

Force is given by

$F_e=Eq\\\Rightarrow F_e=100\times 24\times 10^{-12}\\\Rightarrow F_e=2.4\times 10^{-9}\ N$

The ratio is

$\dfrac{F_e}{F_g}=\dfrac{2.4\times 10^{-9}}{0.12\times 10^{-3}\times 9.81}\\\Rightarrow \dfrac{F_e}{F_g}=0.00000203873598369$

The ratio is $\dfrac{F_e}{F_g}=0.00000203873598369$

Balancing the forces we get

$Eq=mg\\\Rightarrow E=\dfrac{mg}{q}\\\Rightarrow E=\dfrac{0.12\times 10^{-3}\times 9.81}{24\times 10^{-12}}\\\Rightarrow E=49050000\ N/C$

The electric field required is 49050000 N/C

4 0

3 years ago

Please Someone Help me I Need Help ASAP PLEASE

dimaraw [331]

The match making one is Radiation is i think B and Convection i think is C and Conduction i think is A. I think 1 is radiation. Because radiation is transferred between objects or an empty space. Number 2 i think is conduction Because conduction is the transfer of thermal energy between to objects touching. Number 3 i also i think is radiation because radiation transfers between objects. Number 4 i also think is conduction because the spoon was touching a hot pot that was on the stove so then the thermal energy was transferred between the two objects touching. number 5 I think is convection because convection is the transfer of energy by the movement of a fluid, such as air or water. Number 6 i think is radiation because the snake is not touching the lamp and radiation goes all across spaces. Number 7 i think is convection because convection is the movement of a fluid, such as air or water. Hope this helps sorry its so long :)

4 0

3 years ago