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2 years ago

If a runner decreases his velocity from 0m/s to +20m/s in 2.0s, what is was his average acceleration?

Physics

1 answer:

Brrunno [24]2 years ago

5 0

Answer:

-10 m/s²

Explanation:

Average acceleration is change in velocity over change in time.

a = (v − v₀) / (t − t₀)

a = (0 m/s − 20 m/s) / (2 s − 0 s)

a = -10 m/s²

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In an early attempt to understand atomic structure, Niels Bohr modeled the hydrogen atom as an electron in uniform circular moti

AleksandrR [38]

Answer:

The answer is below

Explanation:

Using Coulomb's law of electric field which is:

$F=k\frac{q_1q_1}{r^2}\\\\ k =constant=9*10^9\ Nm^2/C^2,q_1=q_2=1.6*10^{-19}C,r=5.29*10^{-11}m\\\\Substituting\ gives:\\\\F=9*10^9*\frac{(1.6*10^{-19})*(1.6*10^{-19})}{(5.29*10^{-11})^2} =8.22*10^{-8}N\\\\Both\ centripetal\ force\ is\ given\ by:\\\\F=m\frac{v^2}{r} \\\\m = mass\ of \ electron=9.11*10^{-31}g,v=speed\ of\ electron\\\\F=m\frac{v^2}{r} \\\\v=\sqrt{\frac{F*r}{m} } \\\\subsituting:\\\\v=\sqrt{\frac{8.22*10^{-8}*5.29*10^{-11}}{9.11*10^{-31}} } \\\\v=2.18*10^6\ m/s\\\\$

$But\ \omega=\frac{v}{r}=\frac{2.18*10^6}{5.29*10^{-11}} =4.13*10^{17}\\\\\omega=2\pi f; f=frequency\\\\f=\frac{\omega}{2\pi} =\frac{4.13*10^{17}}{2\pi} \\\\f=6.57*10^{15}\ Hz$

6 0

2 years ago

A car travels 3 km north, then turns and travels 4 km west. What is the car's displacement?

Olin [163]

Explanation:

Displacement = Shortest path Travelled from starting point to final point..

Displacement formula = Final position - Initial position

= 7km - 3km

= 4km

^Displacement is 4km

If this answer helps you plz mark as brainlist..

Tq..

5 0

3 years ago

Read 2 more answers

Un tractor halando un carretón cargado con caña de azucar, viaja por el camino recto de una finca a una velocidad de 20 km/h. Si

Sidana [21]

Translation

A tractor pulling a cart loaded with sugar cane travels down the straight path of a farm at a speed of 20 km / h. If at 3:00 p.m.you pass the Finca Las Margaritas, what time will you arrive at the Las Ilusiones farm, located on the same road, if the distance between the two farms is 60 km

Answer:

6.00 pm

Explanation:

Speed is given by dividing distance by time and expressed as s=d/t. Making time the subject of the formula then t=d/s where s is the speed, d is distance covered and t is the time taken. Substituting 20 km/h for s and 60 km for d then t=60/20=3 hours

Adding 3 hours to 3 pm we get 6pm

Therefore, the time to reach the destination if the speed is constantly maintained is 6.00 pm

4 0

3 years ago

A car drives around a curve with a radius of 42 m at a velocity of 24m/s. What is the centripical acceleration of the car?

Vinvika [58]

Answer:

13.71

Explanation:

13.71 miles per hour

7 0

3 years ago

Help please!!! Physics circular motion

svp [43]

Answer:

2. 3.1415 m/s

3. 0.63m

4. 0.006 m/s^2

Explanation:

2. v=(2*pi*r))/T, put in values and solve.

3. Circumference=2*pi*radius, radius is 0.1m, plug in and solve.

4. a=(v^2)/r, (don't worry about converting to meters, since units are the same in kilometers, they will cancel out) plug in values and solve.

That's it!

6 0

2 years ago