A.is an example of decomposition reaction.
We know the formula for density = Mass/ volume
So Mass, M = Volume * Density
Volume = 3.5 L= 0.0035
Density = 1.50 g/ml = 1500 
Mass, M = 0.0035*1500 = 5.25 kg
So mass of liquid having density 1.50 g/ml and volume 3.5 liters is 5.25 kg.
Refer to the diagram shown below.
W₁ = (4 kg)*(9.8 m/s²) = 39.2 N
W₂ = (1 kg)*(9.8 m/s²) = 9.8 N
The normal reaction on the 4-kg mass is
N = (39.2 N)*cos(25°) = 35.5273 N
The force acting down the inclined plane due to the weight is
F = (39.2 N)*sin(25°) = 16.5666 N
The net force that accelerates the 4-kg mass at a m/²s down the plane is
F - W₂ = (4 kg)*(a m/s²)
4a = 16.5666 - 9.8
a = 1.6917 m/s²
Answer: 1.69 m/s² (nearest hundredth)
Все написано в скобках правильно
This problem is about the rate of the current. It's important to know that refers to the quotient between the electric charge and the time, that's the current rate.

Where Q = 2.0×10^−4 C and t = 2.0×10^−6 s. Let's use these values to find I.

<em>As you can observe above, the division of the powers was solved by just subtracting their exponents.</em>
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<h2>Therefore, the rate of the current flow is 1.0×10^2 A.</h2>