1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
MakcuM [25]
3 years ago
13

When determining whether a chemical reaction has taken place, you observe and look for several indicators. Which would be consid

ered an indication that a chemical reaction or chemical change has taken place? A) Solid melts. B) Heat is given off. C) Substance dissolves D) Substance changes shape.
Physics
1 answer:
Inga [223]3 years ago
6 0
The answer is B.

A cannot be the answer is melting is a physical change. No chemical reaction took place.

B is the answer as it is a EXOTHERMIC REACTION so heat will be given off.

C cannot be the answer as dissolving is basically atoms becoming ions, not a chemical reaction whereby a reactant reacts with another reactant to form a product.

D cannot be the answer. Same reason as for why A is not the answer.

Cheers.
You might be interested in
Big Al stands on a skateboard at a rest and throws a 0.5-kilogram rock at a velocity of 10.0 m /sec. Big Al moves back at 0.05 m
Vlada [557]
Let
his and skateboard's combined mass is x
we know
F1=-F2
0.5kg*10m/s=-0.05m/s xkg
5=0.05x(minus cancel with the m/s as it represented the opposite direction of velocity and now there is no velocity in this equation.. so minus is avoidable. and the kgs cancel out)
x=10
so their combined mass is a 100 kg.. (I hope I didn't mess thing up for you)
4 0
3 years ago
An electron that has an instantaneous velocity of ???? = 2.0 × 106 m ???? ???? + 3.0 × 106 m ???? ???? is moving through the uni
Setler79 [48]

Explanation:

It is given that,

Velocity of the electron, v=(2\times 10^6i+3\times 10^6j)\ m/s

Magnetic field, B=(0.030i-0.15j)\ T

Charge of electron, q_e=-1.6\times 10^{-19}\ C

(a) Let F_e is the force on the electron due to the magnetic field. The magnetic force acting on it is given by :

F_e=q_e(v\times B)

F_e=1.6\times 10^{-19}\times [(2\times 10^6i+3\times 10^6j)\times (0.030i-0.15j)]

F_e=-1.6\times 10^{-19}\times (-390000)(k)

F_e=6.24\times 10^{-14}k\ N

(b) The charge of electron, q_p=1.6\times 10^{-19}\ C

The force acting on the proton is same as force on electron but in opposite direction i.e (-k). Hence, this is the required solution.

8 0
3 years ago
Behavioral Adaptations: Behavior that animals begin life with that helps them meet their needs is called ________.
Arturiano [62]
I believe the blank would simply be behaviour adaptations. Behavioural adaptations are behaviours that organisms demonstrate to help them better survive and reproduce in a habitat. Hope that helps!!
6 0
3 years ago
Read 2 more answers
A bucket of mass m is hanging from the free end of a rope whose other end is wrapped around a drum (radius R, mass M) that can r
mr Goodwill [35]

Answer:

Explanation:

Let T be the tension .

Applying newton's second law on the downward movement of the bucket

mg - T = ma

On the drum , a torque of TR will be acting which will create an angular acceleration of α in it . If I be the moment of inertia of the drum

TR = Iα

TR = Ia/ R

T =  Ia/ R²

Replacing this value of T in the other equation

mg - T = ma

mg - Ia/ R²  = ma

mg =  Ia/ R² +ma

a ( I/ R² +m)= mg

a = mg / ( I/ R² +m)

mg - T = ma

mg - ma  = T

mg - m x mg / ( I/ R² +m) = T

mg - m²g / ( I/ R² +m ) = T

mg - mg / ( 1 + I / m R² ) = T

b ) T =  Ia/ R²

I = TR² / a

c ) Moment of inertia of hollow cylinder

I = 1/2  M ( R² - R² / 4 )

= 3/4 x 1/2 MR²

= 3/8 MR²

I / R² = 3/8 M

a = mg / ( I/ R² +m)

a = mg / ( 3/8 M + m )

T =  Ia/ R²

= 3/8 MR² x mg / ( 3/8 M + m ) x 1 /R²

= \frac{3mMg}{(3M +8m)}

7 0
3 years ago
A person is attracted towards the center of the earth by an 800 N gravitational force. The force with which the earth is attract
suter [353]

Answer:

800 N

Explanation:

By Newton's third law which states that for every action, there is an equal and opposite reaction.

So, as the earth attracts the person towards its center, the person attracts the earth towards itself with the same magnitude of force but in the opposite direction.

Since the person is attracted towards the center of the earth by an 800 N gravitational force, the  the earth is attracted toward the person with an 800 N reaction force.

7 0
2 years ago
Other questions:
  • What is the smallest part of a compound called? element atom mixture molecule
    8·2 answers
  • What is the wavelength of a wave with a frequency of 330 Hz and a speed of
    12·1 answer
  • A water wave traves with a length of 10 meters and a frequency of 30 hertz, what is the velocity of the wave?
    9·1 answer
  • What happens when a cold front meets a warm front?
    9·2 answers
  • A test specimen in a tensile test has a gage length of 2.0 in and an area = 0.5in^2. During the test the specimen yields under a
    13·1 answer
  • A bicyclist of mass 60kg supplies 340W of power while riding into a 5 m/s head wind. The frontal area of the cyclist and bicycle
    13·1 answer
  • The United States and South Korean soccer teams are playing in the first round of the World Cup. An American kicks the ball, giv
    13·1 answer
  • Describe the velocity of the object shown by the graph .
    15·2 answers
  • Which phenomenon supports the particle model of light?
    10·2 answers
  • 2h 10min expressed in seconds?<br> Step by step please
    12·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!