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Temka [501]
3 years ago
10

A watt is a measure of power (the rate of energy change) equal to 1 j>s. (a) calculate the number of joules in a kilowatt- ho

ur. (b) an adult person radiates heat to the surroundings at about the same rate as a 100-watt electric incandescent light- bulb. what is the total amount of energy in kcal radiated to the surroundings by an adult in 24 h?
Physics
1 answer:
GalinKa [24]3 years ago
4 0
Before solving this, you must know the definition of these units of measurement. Watt is a measurement of power which is the amount of energy per unit time in seconds. Energy, on the other hand, is expressed through the SI unit Joules. Thus, power is the amount of energy in Joules per second.

From here, you can use the dimensional analysis technique. Also, you should know that 1 kilowatt is equal to 1000 watts, and 24 hours is equal to 86,400 seconds. Then,

100 = Energy/86,400
Energy = 8,640,000 Joules

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Two common terms for a decrease in velocity are
Colt1911 [192]

deceleration or rėtardation i’m pretty sure (it won’t let me say the second word but it’s correct)

6 0
3 years ago
Read 2 more answers
The total energy of a block—spring system is 0.18 J. The amplitude is 14.0 cm and the maximum speed is 1.25 m/s. Find: (a) the m
algol13

a) The mass is 0.23 kg

b) The spring constant is 1.25 N/m

c) The frequency is 1.42 Hz

d) The speed of the block is 1.08 m/s

Explanation:

a)

We can find the mass of the block by applying the law of conservation of energy: in fact, the total mechanical energy of the system (which is sum of elastic potential energy, PE, and kinetic energy, KE) is constant:

E=PE+KE=const.

The potential energy is given by

PE=\frac{1}{2}kx^2

where k is the spring constant and x is the displacement. When the block is crossing the position of equilibrium, x = 0, so all the energy is kinetic energy:

E=KE_{max}=\frac{1}{2}mv_{max}^2 (1)

where

m is the mass of the block

v_{max}=1.25 m/s is the maximum speed

We also know that the total energy is

E=0.18 J

Re-arranging eq.(1), we can find the mass:

m=\frac{2E}{v_{max}^2}=\frac{2(0.18)}{(1.25)^2}=0.23 kg

b)

The maximum speed in a spring-mass system is also given by

v_{max} =\sqrt{\frac{k}{m}} A

where

k is the spring constant

m is the mass

A is the amplitude

Here we have:

v_{max}=1.25 m/s is the maximum speed

m = 0.23 kg is the mass

A = 14.0 cm = 0.14 m is the amplitude

Solving for k, we find the spring constant

k=\frac{v_{max}^2}{A^2}m=\frac{1.25^2}{0.14^2}(0.23)=18.3 N/m

c)

The frequency in a spring-mass system is given by

f=\frac{1}{2\pi}\sqrt{\frac{k}{m}}

where

k is the spring constant

m is the mass

In this problem, we have:

k = 18.3 N/m is the spring constant (found in part b)

m = 0.23 kg is the mass (found in part a)

Substituting and solving for f, we find the frequency of the system:

f=\frac{1}{2\pi}\sqrt{\frac{18.3}{0.23}}=1.42 Hz

d)

We can solve this part by using the law of conservation of energy; in fact, we have

E=PE+KE=\frac{1}{2}kx^2 + \frac{1}{2}mv^2

Where v is the speed of the system when the displacement is equal to x.

We know that the total energy of the system is

E = 0.18 J

Also we know that

k = 18.3 N/m is the spring constant

m = 0.23 kg is the mass

Substituting

x = 7.00 cm = 0.07 m

We can solve the equation to find the corresponding speed v:

v=\sqrt{\frac{2E-kx^2}{m}}=\sqrt{\frac{2(0.18)-(18.3)(0.07)^2}{0.23}}=1.08 m/s

#LearnwithBrainly

3 0
3 years ago
Answer <br> A)<br> B <br> C <br> please
babymother [125]

Answer:

<h2>a is b is c is</h2>

Explanation:

brash this so hard

5 0
2 years ago
What makes a magnet on the atomic level?
yanalaym [24]

Answer:

Magnetism at atomic /sub - atomic levels is mostly due to charged particles called electrons. Electrons have spin which give them angular momentum and thus a magnetic moment associated with it. That is the cause of Magnetism at atomic levels. Electrons fill up orbitals in atoms in pairs.

4 0
3 years ago
A firecracker breaks up into three pieces, one of which has a mass of 200 g and flies off along the x-axis with a speed of 82.0
Mamont248 [21]

Answer:

|P_3|=21.242m/s

Explanation:

From the question we are told that:

Mass m=200g=0.2

Speed v=82.0m/s

Mass M_2=300g=0.3kg

Speed V_2=45.0m/s

Generally the equation for Magnitude of the Third piece is mathematically given by

P_1+P_2+P_3=0

|P_3|=|P_1+P_2|

Where

P_1=m_1v_1

P_1=0.2*82

P_1=16.4kgm/s

And

P_2=0.3*45

P_2=13.5kgm/s

Therefore

|P_3|=\sqrt{16.4^2+13.5^2}

|P_3|=21.242m/s

8 0
3 years ago
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