The correct answer is A. Acid rain forms from human activities and lowers the pH of rainwater below 7
Explanation:
The term "acid rain" is used to refer to rainwater with a low pH or a high acidity, this includes rainwater with a pH below 7 (solutions with a pH under 7 are acidic). In terms of formation, acid rain is mainly the result of human activities such as factories or cars that release pollutants into the atmosphere including nitric and sulfuric acids and these alter the natural pH of rain and makes it more acidic. Additionally, acid rain has negative consequences such as the death of fishes and other organisms in lakes, rivers, etc. because the acidity is toxic to many organisms. Thus, acid rain is the result of human activities and it lowers the pH of rain (Option A).
1. Answer: A skydiver whose air resistance is equal to that of her weight.
A skydiver free falls under gravity but her rate of fall slows down due to drag -air resistance. when this air resistance becomes equal to her weight, the two get balanced and the body does not accelerate or decelerates.
2. Answer: Gravity
Contact forces are those which act when there is physical contact between two bodies. For example: normal force, tension and spring force.
Non-contact forces act between two bodies even when they are at a distance apart. For example: gravity, electric force, magnetic force etc.
3. Answer: The tendency of an object's motion to remain the same.
Inertia is a property of matter by virtue of which it tends to remain in its state of motion or rest. It does depend on mass of the object, more the mass, more is inertia. For example, cycle can be easily moved but we need real push hard for a car to move.
4. Answer: 254 N
The man pushes the box with 310 N force at an angle of 55 degrees to the horizontal.
we can write this in terms of horizontal (
)and vertical component (
).
Horizontal component: 
Vertical component: 
The vertical component would act towards the floor making the job more difficult to move the job.
Answer:
I = 24 A
Explanation:
This is Parallel Circuit and it is the first principle of parallel circuit that voltage will be equal in all components in the circuit
It includes 10 resistors Therefore the voltage across,
R1 = R2 = R3 = R4 = R5 = R6 = R7 = R8 = R9 = R10 = voltage in battery
<h2>
Ohm's Law</h2>
We will apply Ohm's Law to each resistor to find its current because we know the voltage across each resistor is 12 V and the resistance of each resistor is 5Ω
I (R1) = E (R1) / R1
I (R1) = 12v / 5Ω
I (R1) = 2.4 A
The value resistance E of all resistors are same therefore by applying the formula above the value of current in all resistors will be 2.4 A
The Total current in the circuit will be
I (total) = I (1) + I (2) + I (3) + I (4) + I (5) + I (6) + I (7) + I (8) + I (9) + I (10)
I (total) = 2.4 + 2.4 + 2.4 + 2.4 + 2.4 + 2.4 + 2.4 + 2.4 + 2.4 + 2.4
I (total) = 24 A
To solve this we assume
that the gas inside is an ideal gas. Then, we can use the ideal gas
equation which is expressed as PV = nRT. At a constant pressure and number of
moles of the gas the ratio T/V is equal to some constant. At another set of
condition of temperature, the constant is still the same. Calculations are as
follows:
T1 / V1 = T2 / V2
V2 = T2 x V1 / T1
V2 = 659.7 x 28 / 504.7
<span>V2 = 36.60 in^3</span>
B. Reversing the current direction will cause the force deflecting the
wire to be perpendicular to the magnetic field but in the opposite
direction.
