4. How much milk at 5° C needs to be added to 250 g of coffee at 90° C to make the coffee drinkable at 60° C?

A 3.0kg mass tied to a string

dem82 [27]

Answer:

$\boxed{\sf Tension \ in \ the \ string \ (T) = 3 \ kN}$

Given:

Mass (m) = 3.0 kg

Uniform speed (v) = 20 m/s

Length of string (r) = 40 cm = 0.4 m

To Find:

Tension in the string (T)

Explanation:

Tension (T) is the string will be equal to centripetal force ( $\sf F_c$ ).

$\boxed{ \bold{ T = F_c = \frac{m {v}^{2} }{r} }}$

Substituting value of m, v & r in the equation:

$\sf \implies T = \frac{3 \times {20}^{2} }{0.4} \\ \\ \sf \implies T = \frac{3 \times 400}{0.4} \\ \\ \sf \implies T =3 \times 1000 \\ \\ \sf \implies T =3000 \: N \\ \\ \sf \implies T =3 \: kN$

$\therefore$

Tension in the string (T) = 3 kN

5 0

3 years ago

How are scientists able to predict when and where the next eclipse will occur?

ahrayia [7]

Answer:

When the Earth and sun are perfectly lined up, then it will happen. They can tell when it's going to happen.

Explanation:

This is why it only happens in some places. Some days it's not sunny out, so it's not going to happen.

5 0

3 years ago

Gold, which has a mass of 19.32 g for each cubic centimeter of volume, is the most ductile metal and can be pressed into a thin

Dennis_Churaev [7]

Answer:

area = 5733.33 cm²

length = 5.47 × $10^{7}$ cm

Explanation:

Given data

density = 19.32 g/cm³

mass = 33.16 g

thickness = 3.000 µm = 3 × $10^{-4}$ cm

radius r = 1.000 µm = 1 × $10^{-4}$ cm

to find out

area of the leaf and length of the fiber

solution

we know volume formula that is

volume = mass / density

volume = 33.16 / 19.32

volume = 1.72 cm³

we know that volume = thickness × area

so area

area = volume / thickness

area = 1.72 / 3 × $10^{-4}$

area = 5733.33 cm²

and

we know volume = πr²L

so L = volume / πr²

length = 1.72 / π(1× $10^{-4}$ )²

length = 5.47 × $10^{7}$ cm

3 0

3 years ago

A child's top is held in place upright on a frictionless surface. The axle has a radius of ????=3.21 mm . Two strings are wrappe

tekilochka [14]

Answer:

Angular momentum, $L=6.47\times 10^{-3}\ m$

Explanation:

It is given that,

Radius of the axle, $r=3.21\ mm=3.21\times 10^{-3}\ m$

Tension acting on the top, T = 3.15 N

Time taken by the string to unwind, t = 0.32 s

We know that the rate of change of angular momentum is equal to the torque acting on the torque. The relation is given by :

$\tau=\dfrac{dL}{dt}$

Torque acting on the top is given by :

$\tau=F\times r$

Here, F is the tension acting on it. Torque acting on the top is given by :

$\tau=2F\times r$

$2T\times r=\dfrac{L}{t}$

$L=2T\times r \times t$

$L=2\times 3.15\times 3.21\times 10^{-3}\times 0.32$

$L=6.47\times 10^{-3}\ m$

So, the angular momentum acquired by the top is $6.47\times 10^{-3}\ m$ . Hence, this is the required solution.

7 0

3 years ago

When a pendulum is swinging, the velocity is highest at which point?

Tems11 [23]

At the center, when the bob is hanging straight down

3 0

3 years ago