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3 years ago

11

Hot water is added to three times its water at 10 degree Celsius and the resulting temperature at 20 degree Celsius. what is the

initial temperature

2 answers:

Rudik [331]3 years ago

6 0

50 dibdbsis ddjdjendd

mina [271]3 years ago

5 0

50 degrees Celsius is the answer

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A girl and her bicycle have a total mads of 42 kg. At the top of the hill her speed is 4 m/s. The hill is 14.3m high and 112m lo

frosja888 [35]

Answer:

13.78 m/s

Explanation:

Given that:

The mass of the girl & her bicycle = 42 kg

The speed at the top of the hilll= 4 m/s

The height of the hill = 14.3 m

The length of the hill (distance) = 112 m

The frictional force = 20 N

To find the speed at the bottom of the hill; we need to carry out the following processes.

The workdone by gravity = mass × acceleration due to gravity × Δh

= 42 × 9.8 × ( 14.3 - 0 )

= 5885.88 joules

The workdone by the friction = Force × distance = - 20 × 112 (since she is riding down the hill)

The workdone by the friction = -2240 Joules

The initial Kinetic friction = 1/2 mv²

= 1/2 × 42 × 4²

= 336 Joules

The final kinetic energy = Initial Kinetic energy + total work

The final kinetic energy = (336 + 5885.88 - 2240) Joules

The final kinetic energy = 3981.88 Joules

Using the final kinetic energy = 1/2 mv²

3981.88 = 1/2 × 42 × v²

3981.88 = 21 v²

v² = 3981.88/21

v² =189.61

v = $\sqrt{189.61}$

v = 13.78 m/s

Therefore, the speed at the bottom = 13.78 m/s

4 0

3 years ago

Physics. 40 points.<br><br><br>Help please :) (View attached image)

laiz [17]

Answer:

1) 10 m/s 2) 14.1 m/s 3) 6.7 m 4) 11.25 m 5) 4.5 m/s 6) 12 joules

Explanation:

7 0

2 years ago

Two electric charges, held a distance, dd, apart experience an electric force of magnitude, FF, between them. If one of the char

lorasvet [3.4K]

Answer:

$F'=2F$

Explanation:

The Coulomb's law states that the magnitude of the electrostatic force between two charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them:

$F=\frac{kq_1q_2}{d^2}$

In this case, we have $q_1'=2q_1$ :

$F'=\frac{kq'_1q_2}{d^2}\\F'=\frac{k(2q_1)q_2}{d^2}\\F'=2\frac{kq_1q_2}{d^2}\\F'=2F$

3 0

3 years ago

Which of these can be impacted due to climate?

tester [92]

Is it a muti choose or normal i will answer it once for each
muti 1 A B
normal 2 A

3 0

4 years ago

Read 2 more answers

The dial of a scale looks like this: 00.0kg. A physicist placed a spring on it. The dial read 00.6kg. He then placed a metal cha

saveliy_v [14]

Answer:

d. The scale's resolution is too low to read the change in mass

Explanation:

If we want to find the change in energy of the spring, we will have to use the Hooke's Law. Hooke's Law states that:

F = kx

since,

w = Fd

dw = Fdx

integrating and using value of F, we get:

ΔE = (0.5)kx²

where,

ΔE = Energy added to spring

k = spring constant

x = displacement

The spring constant is typically in range of 4900 to 29400 N/m.

So if we take the extreme case of 29400 N/m and lets say we assume an unusually, extreme case of 1 m compression, we get the value of energy added to be:

ΔE = (0.5)(29400 N/m)(1 m)²

ΔE = 1.47 x 10⁴ J

Now, if we convert this energy to mass from Einstein's equation, we get:

ΔE = Δmc²

Δm = ΔE/c²

Δm = (1.47 x 10⁴ J)/(3 x 10⁸ m/s)²

<u>Δm = 4.9 x 10⁻¹³ kg</u>

As, you can see from the answer that even for the most extreme cases the value of mass associated with the additional energy is of very low magnitude.

Since, the scale only gives the mass value upto 1 decimal place.

Thus, it can not determine such a small change. So, the correct option is:

<u>d. The scale's resolution is too low to read the change in mass</u>

8 0

3 years ago