1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
UNO [17]
3 years ago
9

Two red blood cells each have a mass of 9.05×10−14 kg and carry a negative charge spread uniformly over their surfaces. The repu

lsion arising from the excess charge prevents the cells from clumping together. One cell carries −2.10 pC and the other −3.30 pC, and each cell can be modeled as a sphere 3.75×10−6 m in radius. If the red blood cells start very far apart and move directly toward each other with the same speed, what initial speed would each need so that they get close enough to just barely touch? Assume that there is no viscous drag from any of the surrounding liquid.
Physics
1 answer:
Nastasia [14]3 years ago
6 0

Answer:

v = 302.923 m/s

Explanation:

We can answer this question using conservation of energy. Since there is no energy loss (e.g. no viscous drag) the energy when they are far apart and the energy when they barely touch must be the same.

The initial energy must be equal to the sum of their kinetic energies, since they are far apart to feel their electrical interaction.

Ei = (1/2)mv1^2 + (1/2)m*v2^2

Let us consider that they move with the same speed:

Ei = mv^2

If we consider the case when they barely touch, there won't be any kinetic energy, just pure electromagnetic energy:

Ef = k q1q2/(r1+r2) = k q1q2/(2r1)

Since Ei = Ef

v^2 = (k/m) q1q2/(2r1)

where

  k = 8.98755 x10^9 Nm^2/C^2

  m = 9.05 x10^-14 kg

  q1 = −2.10 pC

  q2 = −3.30 pC

  r1 = 3.75×10^−6 m

v^2 = 91762.4 m^2/s^2

v = 302.923 m/s

You might be interested in
What did the Federal Highway Act do?
saw5 [17]

Answer:

c.

Explanation:

5 0
3 years ago
The nucleus of a large atom splits and two smaller atoms are formed. Energy is released in the process. What is the name of this
Ganezh [65]

That process is called "nuclear fission".

4 0
2 years ago
Read 2 more answers
A child of mass 25 kg is skating fast, +10 m/s, and tries to get revenge by colliding with the 60 kg adult who is sitting still.
tankabanditka [31]

Answer: -4.4 m/s

Explanation:

This problem can be solved by the Conservation of Momentum principle, which establishes that the initial momentum p_{o} must be equal to the final momentum p_{f}:

p_{o}=p_{f} (1)

Where:

p_{o}=m_{1}V_{o}+m_{2}U_{o} (2)

p_{f}=m_{1}V_{f}+m_{2}U_{f} (3)

m_{1}=25 kg is the mass of the child

V_{o}=10 m/s is the initial velocity of the child

m_{2}=60 kg is the mass of the adult

U_{o}=0 m/s is the initial velocity of the adult (it is sitting still)

V_{f} is the final velocity of the child

U_{f}=6 m/s is the final velocity of the adult

Substituting (2) and (3) in (1):

m_{1}V_{o}+m_{2}U_{o}=m_{1}V_{f}+m_{2}U_{f} (4)

Isolating V_{f}:

V_{f}=\frac{m_{1}V_{o}-m_{2}U_{f}}{m_{1}} (5)

V_{f}=\frac{(25 kg)(10 m/s)-(60 kg)(6 m/s)}{25 kg} (6)

Finally:

V_{f}=-4.4 m/s This means the velocity of the child is in the opposite direction

4 0
3 years ago
A toy rocket is launched straight up by using a spring. The rocket is initially pressed down on the spring so that the spring is
tigry1 [53]

Answer:

6.86 meters

Explanation:

Let the compression of the string be represented by x, and the height of projection of the toy rocket be represented by h.

So that;

x = 9 cm = 0.09 m

In its rest position (i.e before the launch), the spring has a stored potential energy which is given as;

PE = \frac{1}{2} Kx^{2}

    = \frac{1}{2} x 830 x (0.09)^{2}

    = 415 x 0.0081

    = 3.3615

The potential energy in the string = 3.36 Joules

Also,

PE = mgh

where: m is the mass, g is the gravitational force and h the height.

m = 50 g = 0.05 kg, g = 9.8 ms^{-2}

Thus,

PE = 0.05 x 9.8 x h

3.3615 = 0.05 x 9.8 x h

3.3615 = 0.49h

⇒ h = \frac{3.3615}{0.49}

      = 6.8602

The height of the toy rocket would be 6.86 meters.

4 0
2 years ago
A heat pump operates on a Carnot heat pump cycle with a COP of 8.7. It keeps a space at 248C by consum-ing 2.15 kW of power. Det
Marizza181 [45]

Answer:

<em>Heat of the reservoir is 461.38 K or 188.1 °C</em>

<em>The heating load is 18.705 kW</em>

Explanation:

COP = 8.7

working temperature T_{h} = 248 °C = 248 + 273.3 = 521.3 K

work power W = 2.15 kW

reservoir temperature T_{c} = ?

heating load Q = ?

We know that

COP = Q/W

Q = COP x W = 8.7 x 2.15 = <em>18.705 kW</em>

Also,

COP = \frac{T_{h} }{T_{h}- T_{c}  } = \frac{521.3}{521.3- T_{c}  }

8.7 = \frac{521.3}{521.3- T_{c}  }

4535.31 - 8.7T_{c}  = 521.3

4535.31 - 521.3 = 8.7T_{c}  

4014.01 = 8.7T_{c}  

T_{c}  = 4014.01/8.7 = <em>461.38 K</em>

or 461.38 -273.3 = <em>188.1 °C</em>

3 0
3 years ago
Other questions:
  • What current flow (I) is associated with an input voltage of 5.0V and resistors R1 = 1.5 kiloohms and R2 = 0.5 kiloohms? Calcula
    11·1 answer
  • You want to close an open door by throwing either a 400-g lump of clay or a 400-g rubber ball toward it. you can throw either ob
    9·1 answer
  • Work and how does it measure energy?
    14·2 answers
  • A wave travels through a medium and displaces the particles perpendicular to the direction in which the wave is traveling. This
    10·2 answers
  • An apple drops from a tree and hits the ground in 1.5s what is its speed just before it hits the ground?
    11·1 answer
  • Does a can opener make work easier by increasing force, increasing distance, or changing direction?
    8·1 answer
  • Easy Physics question plz help ASAP
    10·1 answer
  • An Abrams tank has a mass of 62,Ō00 kg. If its top speed is 20.0 m/s, what is its momentum at top speed?
    8·1 answer
  • The 1.5kg ball is launched straight upward with an initial velocity of 7m/s. What is the maximum height it will reach?​
    11·1 answer
  • How much did the pressure drop in the storm's center from November 9, 1200z, until November 11, 0000z
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!