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Nonamiya [84]
3 years ago
11

Alex, parked by the side of an east-west road, is watching car P, which is moving in a westerly direction. Barbara, driving east

at a speed 52 km/h, watches the same car. Take the easterly direction as positive. If Alex measures a speed of 78 km/h for car P, what velocity will Barbara measure?
Physics
1 answer:
Alexxandr [17]3 years ago
6 0

Answer:

v_{PB} = 130\ km/h

Explanation:

Since, Alex is at rest. Therefore, the speed measured by him will be the absolute speed of car P. Therefore, taking easterly direction as positive:

Absolute\ Velocity\ of\ Car\ P = v_{P} = -78\ km/h

And the absolute velocity of Barbara's Car is given as:Absolute\ Velocity\ of\ Barbara's\ Car = v_{B} = 52\ km/h

Now, for the velocity of Car p with respect to the velocity of Barbara's Car can be given s follows:

Velocity\ of\ Car\ P\ measured\ by\ Barbara = v_{PB} = v_{B}-v_{P}\\\\v_{PB} = 52\ km/h-(-78\ km/h)

v_{PB} = 130\ km/h

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Coulomb is a very large unit for practical use. Justify your answer if 10^10 electrons are transferred from a body/second
zlopas [31]
Given:

10^10 electrons per second

To justify that coulomb is a very large unit for practical use, we need to convert the quantity of electron given to Coulombs:

From literature, 

1 Coulomb is equivalent to 6.242×10^18 electrons<span>.

So,

= 10^10 electrons * (1 coulomb/</span><span>6.242×10^18</span> electrons) / second
<span>= 1.602 x 10^-9 coulumbs

This value is too small to be used in an actual setting. 

</span><span>
</span>
3 0
3 years ago
Two balls of equal size are dropped from the same height from the roof of a building. One ball has twice the mass of the other.
frutty [35]

Answer:

The kinetic energy of the more massive ball is greater by a factor of 2.

Explanation:

By conservation of energy, we know that the initial energy = final energy. At first, the balls are dropped from a height with no initial velocity so their initial energy is all potential energy. When they reach the bottom, all their energy is kinetic energy. So all of their energy is changed from potential to kinetic energy. This means that the ball with greater potential energy will have a greater kinetic energy.

Potential energy = mgh. Since g = gravity is a constant and h = height is the same, the only difference is mass. Since mass is directly proportional to potential energy, the greater the mass, the greater the potential energy, so the more massive ball has a greater initial potential energy and will have a greater kinetic energy at the bottom.

Additionally, let B1 = lighter ball with mass m and let B2 = heavier ball with mass m2. Since we know that intial potential energy = final kinetic energy. We can rewrite it as potential energy = kinetic energy = mass * gravity constant * height. For B1, it is mgh and for B2 it is 2mgh, so B2's kinetic energy is twice that of B1.

3 0
3 years ago
How does a parallel circuit differ from a series circuit?
Levart [38]
A series circuit has only one path for current, 
while a parallel circuit has more than one.
4 0
4 years ago
A car has a uniform velocity of 108km/h. How far does it travel in 30 seconds?​
natita [175]
  • Velocity=108km/h

Convert to m/s

\\ \tt\longmapsto 108\times \dfrac{5}{18}

\\ \tt\longmapsto 30m/s

  • Time=30s.

\\ \tt\longmapsto Distance=Velocity\times Time

\\ \tt\longmapsto Distance=30(30)

\\ \tt\longmapsto Distance=900m

6 0
3 years ago
A reactor operating at 1 MW is scrammed by instantaneous insertion of $5.00 of negative reactivity. Approximately how long does
Novosadov [1.4K]

Answer:

time is 3333.33 min or 55.55 hr

Explanation:

given data

reactor operating = 1 MW

negative reactivity =  $5

power = 1 miliwatt

to find out

how long does it take

solution

we know here power coefficient that is

power coefficient = \frac{10^{6} }{10^{6} }

power coefficient = 1

so time required to reach power is

power =  reactivity × time / power coefficient + reactor operating

1 × 10^{-3} = -5 t / 1  +  1 × 10^{6}

5t =  10^{6} - 10^{-3}

t = 199999.99 sec

so time is 3333.33 min or 55.55 hr

4 0
3 years ago
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