Complete Question:
Metal sphere A has a charge of − Q . −Q. An identical metal sphere B has a charge of + 2 Q . +2Q. The magnitude of the electric force on sphere B due to sphere A is F . F. The magnitude of the electric force on sphere A due to sphere B must be:
A. 2F
B. F/4
C. F/2
D. F
E. 4F
Answer:
D.
Explanation:
If both spheres can be treated as point charges, they must obey the Coulomb's law, that can be written as follows (in magnitude):

As it can be seen, this force is proportional to the product of the charges, so it must be the same for both charges.
As this force obeys also the Newton's 3rd Law, we conclude that the magnitude of the electric force on sphere A due to sphere B, must be equal to the the magnitude of the force on the sphere B due to the sphere A, i.e., just F.
The change in momentum of the car is 45,000 kg m/s
Explanation:
The change in momentum of an object is given by:

where
m is the mass of the object
u is its initial velocity
v is its final velocity
For the car in this problem, we have
m = 900 kg
u = 30 m/s
v = 80 m/s
Therefore, the change in momentum is:

Learn more about momentum:
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The law of Ohm defines the relationship in an electrical circuit between voltage, current and resistance: I = v / r. The current is directly proportional to the voltage and the resistance is inversely proportional.
It’s going 3m/s. If we have 5 seconds to work with then we can find the acceleration by adding speed and how fast it going every second. So like the 7-10-13-16-19 so we go 3m/s faster ever second