Answer:
The resultant force would (still) be zero.
Explanation:
Before the 600-N force is removed, the crate is not moving (relative to the surface.) Its velocity would be zero. Since its velocity isn't changing, its acceleration would also be zero.
In effect, the 600-N force to the left and 200-N force to the right combines and acts like a 400-N force to the left.
By Newton's Second Law, the resultant force on the crate would be zero. As a result, friction (the only other horizontal force on the crate) should balance that 400-N force. In this case, the friction should act in the opposite direction with a size of 400 N.
When the 600-N force is removed, there would only be two horizontal forces on the crate: the 200-N force to the right, and friction. The maximum friction possible must be at least 200 N such that the resultant force would still be zero. In this case, the static friction coefficient isn't known. As a result, it won't be possible to find the exact value of the maximum friction on the crate.
However, recall that before the 600-N force is removed, the friction on the crate is 400 N. The normal force on the crate (which is in the vertical direction) did not change. As a result, one can hence be assured that the maximum friction would be at least 400 N. That's sufficient for balancing the 200-N force to the right. Hence, the resultant force on the crate would still be zero, and the crate won't move.
Answer:
Work done to pull the piano upwards is 401250 J
Explanation:
Work is done against the gravity to pull the piano upwards
So here we can say that work done is
here we know that
also we know that
H = 75 m
now we have
The answer is 3
I hope I helped
Answer:
1. Ptolemy.
2. Nicolaus Copernicus.
3. Tycho Brahe
4. Galileo Galilei
5. Isaac Newton
6. William Herschel
7. Johann Galle
8. Clyde Tombaugh
9. Albert Einstein.
10. Edwin Hubble
11. Karl Jansky.
12. Grote Weber.
Explanation:
1. Ptolemy: said sun revolved around earth.
2. Nicolaus Copernicus: aid earth revolved around sun.
3. Tycho Brahe: analyzed motions of planets.
4. Galileo Galilei: first used refracting telescope for astronomy.
5. Isaac Newton: invented reflecting telescope.
6. William Herschel: discovered the planet Uranus.
7. Johann Galle: discovered the planet Neptune.
8. Clyde Tombaugh: discovered the dwarf planet Pluto.
9. Albert Einstein: developed special and general theories of relativity.
10. Edwin Hubble: demonstrated that universe is expanding.
11. Karl Jansky: discovered radio waves from the center of the Milky Way.
12. Grote Weber: an amateur astronomer who built the first radio telescope.
