All categories

4 years ago

What do you mean by physical quantity

2 answers:

7 0

A physical quantity is something which can be measured and whose measurement is necessary because all the laws of physics are given in terms of these physical quantities. The examples of physical quantity are mass, length, time, temperature, electric current, velocity , acceleration, force, work, weight,power, energy etc.

There are some quantities which cannot be measured and hence are not classified as physical quantities , for example, love, honesty, hatred etc

Thus a physical quantity is a quantity which can be measured.

Zinaida [17]4 years ago

6 0

Is mean something the you can measure with lenght weight time of fall

You might be interested in

A snowball with a mass of 85 g hits the top hat of a 1.5 m tall snowman and sticks to it. the hat and the snowball, with a combi

LenaWriter [7]

Part (a): Velocity of the snowball
By conservation of momentu;
m1v1 + m2v2 = m3v3,

Where, m1 = mass of snowball, v1, velocity of snowball, m2 = mass of the hat, v2 = velocity of the hat, m3 = mass of snowball and the hat, v3 = velocity of snowball and the hut.

v2 = 0, and therefore,
85*v1 + 0 = 220*8 => v1 = 220*8/85 = 20.71 m/s

Part (b): Horizontal range
x = v3*t
But,
y = vy -1/2gt^2, but y = -1.5 m (moving down), vy =0 (no vertical velocity), g = 9.81 m/s^2

Substituting;
-1.5 = 0 - 1/2*9.81*t^2
1.5 = 4.905*t^2
t = Sqrt (1.5/4.905) = 0.553 seconds

Then,
x = 8*0.553 = 4.424 m

7 0

3 years ago

How much work must be done to bring three electrons from a great distance apart to 3.0×10−10 m from one another (at the corners

Natasha_Volkova [10]

Answer:

$Potential\ Energy=Work \ Done=2.301*10^{-18} J$

Work done to bring three electrons from a great distance apart to 3.0×10−10 m from one another (at the corners of an equilateral triangle) is $2.301*10^{-18} Joules$

Explanation:

The potential energy is given by:

U=Q*V

where:

Q is the charge

V is the potential difference

Potential Difference=V= $\frac{kq}{r}$

So,

$Potential\ Energy=\frac{Qkq}{r} \\Q=q\\Potential\ Energy=\frac{kq^2}{r}$

Where:

k is Coulomb Constant= $8.99*10^9 Nm^2/C^2$

q is the charge on electron= $-1.6*10^-19 C$

r is the distance= $3.0*10^{-10}m$

For 3 Electrons Potential Energy or work Done is:

$Potential\ Energy=3*\frac{kq^2}{r}$

$Potential\ Energy=3*\frac{(8.99*10^9)(-1.6*10^{-19})^2}{3*10^{-10}}\\Potential\ Energy=2.301*10^{-18} J$

Work done to bring three electrons from a great distance apart to 3.0×10−10 m from one another (at the corners of an equilateral triangle) is $2.301*10^{-18} Joules$

7 0

3 years ago

.You have always been impressed by the speed of the elevators in your apartment building. You wonder about the maximum accelerat

AlexFokin [52]

Answer:

5.51 m/s^2

Explanation:

Initial scale reading = 50 kg

assume the greatest scale reading = 78.09 kg

Determine the maximum acceleration for these elevators

At rest the weight is = 50 kg

Weight ( F ) = mg = 50 * 9.81 = 490.5 N

At the 10th floor weight = 78.09 kg

Weight at 10th floor ( F ) = 78.09 * 9.81 = 766.11 N

F = change in weight

Change in weight( F ) = ma = 766.11 - 490.5 (we will take the mass as the starting mass as that mass is calculated when the body is at rest)

50 * a = 275.61

Hence the maximum acceleration ( a ) = 275.61 / 50 = 5.51 m/s^2

3 0

3 years ago

How do you know that a chemical change has happened

Elodia [21]

Answer:

theres is many states of chemical change but its not exaclty the same as physical the appearence might change alittle but chemical like frying a egg is a chemical change because a change of materials into another, new materials with different properties and one or more than one new substances are formed and the subtance changeing or the materials can show chemical changed happened you cant always see it but touching too like heat energy can show a chemical change

Explanation:

i hope this helps and keep ur grades up :)

6 0

2 years ago

Read 2 more answers

Which of the following is NOT a good example of a short-term goal?

Molodets [167]

Loose 10 pounds im pretty sure

5 0

4 years ago