The group of test subject that are NOT given the experimental treatment is called what?

A negatively charged object is brought near the knob of a negatively charged electroscope. The leaves of the electroscope will..

vladimir1956 [14]

Move farther apart because like charges repel each other.

5 0

3 years ago

A horizontal force of magnitude 46.3 n pushes a block of mass 4.14 kg across a floor where the coefficient of kinetic friction i

IrinaVladis [17]

A) Calling F the intensity of the horizontal force and d the displacement of the block across the floor, the work done by the horizontal force is equal to
$W=Fd = (46.3 N)(4.25 m)=196.8 J$

b) The work done by the frictional force against the motion of the block is equal to:
$W_f = -F_f d =- (\mu mg) d =-(0.609)(4.14 kg)(9.81 m/s^2)(4.25 m)=$
$=-105.1 J$
Part of these 105.1 Joules of work becomes increase of thermal energy of the block ( $\Delta E_B$ ), and part of it becomes increase of thermal energy of the floor ( $\Delta E_F$ ). We already know the increase in thermal energy of the block (38.2 J), so we can find the increase in thermal energy of the floor:
$\Delta E_F = 105.1 J - \Delta E_B = 105.1 J-38.2 J=66.9 J$

c) The net work done on the block is the work done by the horizontal force F minus the work done by the frictional force (the frictional force acts against the motion, so we must take it with a negative sign):
$W_{net}=W-W_f=196.8 J-105.1 J=91.7 J$
For the work-energy theorem, the work done on the block is equal to its increase of kinetic energy:
$W_{net} = \Delta K$
So, we have $\Delta K=+91.7 J$

5 0

3 years ago

A crude model of the human throat is that of a pipe open at both ends with a vibrating source to introduce the sound into the pi

viva [34]

Answer:Changing Length

Explanation:

We know the Resonant frequency depends upon length and varies as inversely to the length of air column

$frequency\propto \frac{1}{L}$

thus by changing the length of Pipe we can chnge the frequency

8 0

3 years ago

What is the momentum of an 8kg bowling ball rolling at 2m/s

NISA [10]

Answer:

16kg m/s

Explanation:

P=mv

8 times 2=16kg m/s

3 0

3 years ago

construct an analogy between a pond/pump system with a water fall (gravitational potential) and a circuit with a battery with se

IRISSAK [1]

Explanation:

Pond $\sim$ Battery

In the two systems, pond acts as water reservoir while battery acts as reservoir in the electrical system.

Water $\sim$ charges

In the pond system the water acts as the main constituent of flow of energy and in electrical system the charges act as the constituent of flow of energy.

Gravitational potential $\sim$ Electric Potential

We have the gravitational potential of the stored water in the pond with respect to the destination which leads to the flow of water whereas the electrical system has the potential difference leading to the flow of charges.

Pipe line $\sim$ Conducting wire

The channel through which the water flows is pipe whereas the path through which the charges flow is conductor.

Tap $\sim$ light bulbs

Output of the pond system is obtained at the taps whereas the output of the electrical system is obtained at the light bulbs.

Drag, viscosity, surface friction $\sim$ electrical resistance

The resistance to the flow of water can be regarded as drag, mechanical friction and viscosity while the electrical resistance is due to the bonded electrons.

volume flow rate $\sim$ current flow

The rate of flow of water is known as the volume flow rate whereas the rate of flow of charges is called current.

3 0

3 years ago