The amount of heat needed to increase the temperature of a substance by

is given by

where
m is the mass of the substance

the specific heat capacity

the increase in temperature
In our problem, the mass of the water is m=750 g, the specific heat is

and the amount of heat supplied is

, so if we re-arrange the previous formula we find the increase in temperature of the water:
Answer:
B. Attract each other with a force of 10 newtons.
Explanation:
Statement is incorrectly written. <em>The correct form is: A </em>
<em> charge and a </em>
<em> at a distance of 0.3 meters. </em>
The two particles have charges opposite to each other, so they attract each other due to electrostatic force, described by Coulomb's Law, whose formula is described below:
(1)
Where:
- Electrostatic force, in newtons.
- Electrostatic constant, in newton-square meters per square coulomb.
- Magnitudes of electric charges, in coulombs.
- Distance between charges, in meters.
If we know that
,
and
, then the magnitude of the electrostatic force is:


In consequence, correct answer is B.
Answer:
Magnitude of the average force exerted on the wall by the ball is 800N
Explanation:
Given
Contact Time = t = 0.05 seconds
Mass (of ball) = 0.80kg
Initial Velocity = u = 25m/s
Final Velocity = 25m/s
Magnitude of the average force exerted on the wall by the ball is given by;
F = ma
Where m = 0.8kg
a = Average Acceleration
a = (u + v)/t
a = (25 + 25)/0.05
a = 50/0.05
a = 1000m/s²
Average Force = Mass * Average Acceleration
Average Force = 0.8kg * 1000m/s²
Average Force = 800kgm/s²
Average Force = 800N
Hence, the magnitude of the average force exerted on the wall by the ball is 800N
Answer:
4 smaller disks
Explanation:
We are given;
Mass of smaller and larger disks = M
Radius of smaller disk = R
Radius of larger disk = 4R
Formula for moment of inertia about cylinder axis is:
I = ½MR²
Thus;
For small disk, I_small = ½MR²
For large disk, I_large = ½M(2R)² = 2MR²
We are told that moment of inertia of System A consists of two of the larger disks. Thus;
I_A = 2 × I_large = 2 × 2MR²
I_A = 4MR²
We are also told that System B consists of one of the larger disks and a number of the smaller disks. Thus;
I_B = I_large + n(I_small)
Where n is the number of smaller disks.
I_B = 2MR² + n(½MR²)
I_B = MR²(2 + n/2)
We are told that the moment of inertia for system A equals the moment of inertia for system B. Thus;
I_A = I_B
So;
4MR² = MR²(2 + n/2)
MR² will cancel out to give;
4 = 2 + n/2
Multiply through by 2 to give;
8 = 4 + n
n = 8 - 4
n = 4
Answer: THE ANSWER IS C!
The total energy of a system can decrease only if energy leaves the system.
Explanation: Apex!