Answer:
False
Explanation:
The given statement "Two objects must be in contact for them to exert a force on each other" is not true as there are many types of forces that doesn't require being in contact for exerting a force.
One such example is the gravitational force acting between two bodies. Gravitational force is the force of pull with which a body pulls another body without being in contact.
For two bodies of masses 'M' and 'm' separated at a distance of 'R', the gravitational force is given as:
The gravitational force acts always act between bodies that have mass. The bodies are not in contact yet experience force.
Therefore, the given statement is false.
Answer:
<h2>1) there is no work done on the system</h2><h2>2) A) Using a lever to lift 100 newtons up to 4 meters on to a shelf</h2><h2 /><h2>3) P = 140 W</h2><h2>4) D) In a closed system, a system that isolated from its surrounds, the total energy of the system is conserved</h2>
Explanation:
1) As we know that work done is the product of force and the displacement of the point of action where force is applied
So here we have
as there is no displacement in the direction where the force is applied
2)As we know that work is product of force and displacement
So we will have
So maximum work is done on
A) Using a lever to lift 100 newtons up to 4 meters on to a shelf
3)
As we know that power is rate of work done
so we have
4)
As per energy conservation we know that
D) In a closed system, a system that isolated from its surrounds, the total energy of the system is conserved
The asteroid's mass is so small that it has a much smaller acceleration
due to gravity than Earth has. That means that things weigh very very little
on the surface of an asteroid. It also means that the "escape velocity" from
an asteroid is very low, and orbital velocities are very low at any distance off
of its surface.
As an extreme example: You know how when you walk, you naturally rise up
on the toes of one foot while you reach out with the other one to take a step ?
All of those motions are what you learn in Earth's gravity. On an asteroid, that
natural action of rising up on your toes might launch you into a long, high arc,
like a golf ball. Or it might even exceed escape velocity and you'd sail up off
of the asteroid and never come back down to it.
The formula to use is: I = (<span> ΔV / R )
Once you solve for R, your new formula would be: R= (</span><span> ΔV / I )
Plug in your values to get: R = (1.5V / .75A )
Finally, R = 2</span><span>Ω</span>
The Sun is going down, and most of the land is dark, but we can see silhouettes and outlines of objects because some light is still scattered the atmosphere. When sunlight reaches Earth's atmosphere it is scattered in all directions by all the gases and particles in the air.Blue is scattered more than other colors because it travels as shorter, smaller waves and is scattered in all directions.
