This question is off-base and misleading from the beginning.
When you jump off the Earth, your momentum changes, <em>and the Earth moves away from you with an equal change of momentum in the opposite direction</em>.
1). Momentum is conserved when you jump. But we don't feel the Earth moving. Since the Earth's mass is a bazillion times greater than YOUR mass, the speed with which the Earth moves away from you is only one bazillionth of your speed. That way, the product of (mass) x (speed) is the SAME for you and for the Earth, and momentum is conserved.
2). <em>Of course !</em> If everyone jumped at the same time, the Earth's momentum would change. In answer-(1), I explained that the Earth's momentum changes whenever <em>ONE PERSON</em> jumps. So 7 billion people all jumping at the same time would certainly make it change.
Answer:
Displacement by cyclist is zero.
Explanation:
In the given question bicyclist is travelling in a rectangular track having P , Q and R edges.
The bicyclist starts from P and travel through Q and R and returned to P again.
We need to find its displacement.
We know displacement of a body is its difference between its initial position to final position.
Here in the given question the bicyclist returns to P again.
Therefore, total displacement by bicyclist is zero.
Hence, this is the required solution.
Light / Radiation. The light radiation defines its color. Thermal radiation for its temperature and the overall appearance of the wavelengths the star emits gives off the info from where astronomers and scientist are able to build up knowledge on the age and current state of the stars
When both sides of an equation give the same units, same numerical values, and same concept we refer to the equation as being correct. ... Removing constants from correct equations make them homogeneous but incorrect.
Answer:

Explanation:
Electrostatic Forces
The force exerted between two point charges
and
separated a distance d is given by Coulomb's formula

The forces are attractive if the charges have different signs and repulsive if they have equal signs.
The problem described in the question locates three point charges in a straight line. The charges have the values shown below


The distance between
and
is

The distance between
and
is

We must find the value of
such that

Applying Coulomb's formula for
is

Now for 

If the total force on
is zero, both forces must be equal. Note that being q2 negative, the force on q3 is to the right. The force exerted by q1 must go to the left, thus q1 must be positive. Equating the forces we have:


Simplfying and solving for 


