1. A) A ball sits motionless on the ground
Newton's First Law of inertia states that:
"When the forces acting on an object are balanced, the object stays at rest (if it was at rest) or continues its motion with constant velocity (if it was in motion)"
Among the options given, we see that the option
A) A ball sits motionless on the ground
is an example of this law: in fact, the ball sits at rest on the ground, the forces acting on it are balanced, so the ball stays at rest.
2. B) The earth pulls more on the shuttle
The gravitational attraction exerted by a planet on the shuttle is given by
where
G is the gravitational constant
M is the mass of the planet
m is the mass of the shuttle
r is the distance between the shuttle and the planet
In this problem, we are comparing the gravitational pulls exerted by the Earth and the Moon on the shuttle. The distance, r, is the same (because the shuttle is half-way), the mass of the shuttle m is the same, and G is the same. However, the mass of the Earth is greater than the mass of the Moon, so in the formula M is greater for the Earth: therefore, the Earth pulls more on the shuttle.
3. B) The velocity of the car reduced from 50 km/h to 35 km/h over one minute
The acceleration of the car is defined as the ratio between the change in velocity and the time taken:
where vf is the final velocity, vi is the initial velocity, and is the time taken.
In order to have a negative acceleration, the numerator must be negative: this means that the initial velocity, vi, must be greater than the final velocity, vf, and this situation occurs in option B), since the initial velocity is 50 km/h while the final velocity is 35 km/h.
1-a 2-b 3-b
srry had to write more, i go to this school
Power in physics is the rate of energy transferred per unit time. It can be calculated by dividing the amount of energy transferred by the time required for the transfer.
In Physics, power is defined as the rate of transferring energy or the amount of energy per unit time. If you want to calculate the power, you take the amount of energy transferred and divide it by the time it takes for that transfer to occur. For example, if a light bulb transfers 100 joules of energy over 10 seconds, the power would be 100 joules divided by 10 seconds, which equals to 10 watts.
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Answer:
Seven
Explanation:
Because all halogens have seven valence electrons, they are “eager” to gain one more electron. Doing so gives them a full outer energy level, which is the most stable arrangement of electrons. Halogens often combine with alkali metals in group 1 of the periodic table.
Answer:
Halogens only need one electron to complete their valkance shells.
Explanation:
Halogens are present in the VIIA group of the periodic table so seven electrons are already present. one is needed to become stable.
radio waves bc they have the longest wave lenthgs in a magnetic spectrum