Anyone could answer this question

Two 20.0 g ice cubes at − 20.0 ∘ C are placed into 285 g of water at 25.0 ∘ C. Assuming no energy is transferred to or from the

Lelechka [254]

Answer:

Ft = 17.48°C

Explanation:

Ft is the final temperature. However, ice absorbs heat during two process of melting and cooling and as such, there is no loss of heat to or from the surrounding hence by conservation of energy.

Therefore,

Heat absorbed by water of 20g = heat rejected by water of 265g.

So; M(ice)[C(ice) [(ΔT) + LH(ice) + C(water)(ΔT)] = C(water) M(water) (ΔT)

So, 20[(2.108) [0 - (-20)] + 333.5 + 4.187(Ft - 0)]] = (285)(4.187) (25 - Ft)

To get;

7513 + 83.74 Ft = 29832.4 - 1193.3 Ft

So factorizing, we get;

83.74 Ft + 1193.3 Ft = 29832.4 - 7513

So; 1277.04 Ft = 22319.4

So; Ft = 22319.4/1277.04 = 17.48°C

7 0

3 years ago

From the gravitational law calculate the weight W (gravitational force with respect to the earth) of a 89-kg man in a spacecraft

zhannawk [14.2K]

Answer:

$W=\frac{773}{4.45}=173.76 l b f$

Explanation:

$W=\frac{G \cdot m_{e} \cdot m}{(R+h)^{2}}$

The law of gravitation

$G=6.673\left(10^{-11}\right) m^{3} /\left(k g \cdot s^{2}\right)$

Universal gravitational constant [S.I. units]

$m_{e}=5.976\left(10^{24}\right) k g$

Mass of Earth [S.I. units]

$m=89 kg$

Mass of a man in a spacecraft [S.I. units]

$R=6371 \mathrm{~km}$

Earth radius [km]

Distance between man and the earth's surface

$h=261 \mathrm{~km} \quad[\mathrm{~km}]$

ESULT $W=\frac{6.673\left(10^{-11}\right) \cdot 5.976\left(10^{24}\right) \cdot 89}{\left(6371 \cdot 10^{3}+261 \cdot 10^{3}\right)^{2}}=773.22 \mathrm{~N}$

$W=\frac{773}{4.45}=173.76 l b f$

4 0

3 years ago

2. A body is thrown vertically upward with a speed of 100 m/s.The time taken to be

Pachacha [2.7K]

Answer:

b. 20 sec

Explanation:

y = y₀ + v₀ t + ½ g t²

0 = 0 + (100) t + ½ (-10) t²

0 = 100t − 5t²

0 = t (100 − 5t)

t = 0, t = 20

The body lands after 20 seconds.

4 0

3 years ago

The amplitude of a standing sound wave in a long pipe closed at the left end is sketched below. The vertical axis is the maximum

Rudiy27

Answer:

Check the explanation

Explanation:

A) 7th Harmonic. (Of an open ended pipe, odd harmonics are allowed (3rd overtone))

b) f = n v / 4 L

n = 7

f = 7 x 350 / 4 x 0.41 = 1493.9 Hz

c) Let level of water H, If reduces the effective length of pipe

Using, f = n v / 4 Leff

n = 1

251.8 = 1 x 350 / 4 ( 0.41 - H)

H = 0.0625m

H = 6.25 cm

5 0

3 years ago

What is the magnetic field amplitude of an electromagnetic wave whose electric field amplitude is 10v/m?

Nitella [24]

Answer:

$3.33\cdot 10^{-8} T$

Explanation:

For an electromagnetic wave, the relationship between magnetic field amplitude and electric field amplitude is given by

$E=cB$

where

E is the amplitude of the electric field

c is the speed of light

B is the amplitude of the magnetic field

For the electromagnetic wave in this problem, we have

E = 10 V/m is the amplitude of the electric field

So if we solve the formula for B, we find the amplitude of the magnetic field:

$B=\frac{E}{c}=\frac{10 V/m}{3\cdot 10^8 m/s}=3.33\cdot 10^{-8} T$

4 0

3 years ago