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3 years ago

What is units and dimensions? what are dimensions less quantities?

Physics

1 answer:

tensa zangetsu [6.8K]3 years ago

3 0

Answer:

A dimension is a measure of a physical variable.

Unit is a way to assign a number or measurement to that dimension.

In dimensional analysis, a dimensionless quantity is a quantity to which no physical dimension is assigned, also known as a bare, pure, or scalar quantity or a quantity of dimension one, with a corresponding unit of measurement is the SI of the unit one, which is not explicity shown.

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7. A toy car of mass 1.2 kg is driving vertical circles inside a hollow cylinder of radius 2.0m. It is moving at a constant spee

wlad13 [49]

Answer:

$N_{top}=9.8N\\N_{bottom}=33.4N$

b) $v_{min}=4.4m/s$

Explanation:

The net force on the car must produce the centripetal acceleration necessary to make this circle, which is $a_{cp}=\frac{v^2}{R}$ . At the top of the circle, the normal force and the weight point downwards (like the centripetal force should), while at the bottom the normal force points upwards (like the centripetal force should) and the weight downwards, so we have (taking the upwards direction as positive):

$-m\frac{v^2}{R}=-N_{top}-mg\\m\frac{v^2}{R}=N_{bottom}-mg$

Which means:

$N_{top}=m\frac{v^2}{R}-mg=(1.2kg)\frac{(6m/s)^2}{2m}-(1.2kg)(9.8m/s^2)=9.8N\\N_{bottom}=m\frac{v^2}{R}+mg=(1.2kg)\frac{(6m/s)^2}{2m}+(1.2kg)(9.8m/s^2)=33.4N$

The limit for falling off would be $N_{top}=0$ , so the minimum speed would be:

$0=m\frac{v_{min}^2}{R}-mg\\v_{min}=\sqrt{Rg}=\sqrt{(2m)(9.8m/s^2)}=4.4m/s$

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3 years ago

The distiction between long and short term memory

RUDIKE [14]

Answer:

The main difference between short term and long term memory is that the short term memory stores data temporarily while the long term memory stores data permanently. Moreover, the short term memory is volatile while the long term memory is nonvolatile. Memory is the component in a computer that stores data and information.

Explanation:

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3 years ago

If the _____ work on a simple machine equals the output work, the machine is said to be 100% efficient.

omeli [17]

<h3>Answer:</h3>

Input work

<h3>Explanation:</h3>

Concept being tested: Efficiency of machines

Therefore we need to know what is the efficiency of a machine

Efficiency of a machine is the ratio of work output of machine to the work input expressed as a percentage.

Thus;

Efficiency = (Work output ÷ Work input) × 100%

Therefore, if the work input is equal to the work output then the efficiency of the machine will be 100%.

Most machines are not 100% efficient due to loss of energy in form of heat due to friction of the moving parts of the machine.

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3 years ago

What is the difference between current electricity and static electricity

Allisa [31]

Answer:

The most significant difference between the static and current electricity is that in static electricity the charges are at rest and they are accumulating on the surface of the insulator. Whereas in current electricity the electrons are moving inside the conductor.

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3 years ago

Read 2 more answers

Please help.......

IceJOKER [234]

Answer:

(L: Length, T: Time)

p: Dimension: L; unit: m

q: Dimension: L/T or (L)*(T)^-1; unit: m/s

r: Dimension: L/T^2 or (L)*(T)^-2; unit: m/s^2

Explanation:

since y is distance (Length), make all terms L distance.

p is same as y dimension ==> dimension: L; unit: m (meter)

qt dimension is L ==> q dimension :L/T; unit: m/s

rt^2 dimension is L ==> r dimension : L/T^2; unit: m/s^2

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2 years ago

What is units and dimensions? what are dimensions less quantities?​

What is units and dimensions? what are dimensions less quantities?