No additional force is required because it's already going downhill
Answer:
Option D
2 m/s East
Explanation:
From the law of conservation of momentum, the sum of initial momentum equals the sum of final momentum
Momentum, p=mv where m is the mass and v is the velocity
Since the masses are the same then
Therefore
where 
and 
are final velocities of objects while 
and 
are the initial velocities respectively
Taking East direction as positive then West as negative and by substitution
Therefore
hence East since it's positive
Use the relation between electric force and electric field and the concept of gravitational force to calculcate the electric field. The electric force is given by
And the gravitational force is
For the ball to float above the ground, the magnitude of electric force on the ball must be equal to the magnitude of the gravitational force. That is must be a equilibrium condition, so,
Replacing the values we have that,
Therefore the electric field magnitude that would cause the ball to float above the ground is 
Answer:
The moist air mass would be denser
Explanation:
Density is defined as mass per unit volume. Hence the density of a substance (solid, liquid or gas) is directly proportional to its mass and inversely proportional to the volume occupied.
The mass of a gas is the product of its number of moles and its molar mass (mass = number of moles × molar mass), which indicates that the mass is directly proportional to molar mass, so the higher the molar mass, the higher the mass of different gases at equal volumes, temperature and pressure.
From the information given, the molar weight of dry air = 29g/mole.
The molar weight of moist air = molar weight of dry air + molar weight of water vapour = 29 + 18 = 47g/mole.
Therefore since higher molar mass transits to higher mass, it can be said that moist air of molar mass 47g/mole is denser than dry air of molar mass 29g/mole at equal volume, temperature and pressure.
Simple picture the two gasses in two transparent jars, the heavier gas (moist air) settles more at the bottom of the jar, and has less random motion hence is more compressed and denser, than dry air that has more freedom to move randomly because of its lesser weight.
Answer:
Open circuit
Explanation:
An open circuit is simply an electrical circuit that is not complete. In such a circuit, there is a gap and this will not allow the electric current to pass through.
Despite all the elements being complete in the circuit, an open circuit will halt the flow of electric current and will not do deliver the necessary energy it is supposed to.
In such a circuit, the wires are cut of and not connected properly.
The reverse is a closed circuit.
