# Force, motion and energy problems and answers

Recent questions in Force, Motion and Energy
agrejas0hxpx 2022-05-10

### Two objects, with masses ${m}_{1}$ and ${m}_{2}$, attract each other with force $F$. If the mass of ${m}_{1}$ increased by a factor of two then the new gravitational force would be: F/42 F4 FF/2

Azzalictpdv 2022-05-10

### Why do two bodies of different masses fall at the same rate (in the absence of air resistance)?I'm far from being a physics expert and figured this would be a good place to ask a beginner question that has been confusing me for some time.According to Galileo, two bodies of different masses, dropped from the same height, will touch the floor at the same time in the absence of air resistance.BUT Newton's second law states that $a=F/m$, with $a$ the acceleration of a particle, $m$ its mass and $F$ the sum of forces applied to it.I understand that acceleration represents a variation of velocity and velocity represents a variation of position. I don't comprehend why the mass, which is seemingly affecting the acceleration, does not affect the "time of impact".Can someone explain this to me? I feel pretty dumb right now :)

ureji1c8r1 2022-05-09

### Does Acceleration due to Gravity take into consideration the centrifugal acceleration due to Earth's spin?Is the gravitational acceleration we consider only the attraction due to the Earth's gravity or is it that of gravity plus the attraction due to Earth spinning?We know that earth produces an acceleration towards the centre on any body near it due to gravitational attraction.We denote this acceleration as $g$But we also know that any body on Earth is also undergoing rotational motion due to earth's Spin. So every body should experience an outward centrifugal acceleration.Does acceleration due to gravity $g$ take the centrifugal acceleration into consideration?

enclinesbnnbk 2022-05-09

### A book is lifted upward a vertical distance of 0.800 m. Duringthis displacement, does the gravitational force acting on the book do positivework or negative work? Does the gravitational potential energy of thebook increase or decrease?

rockandriot0odjn 2022-05-09

### 1. Why is gravitational force always an attractive force?2. And is the Newtonian formula of gravitational force applicable for very small particles like electrons and protons etc.? From Formula of Gravitational Force, I'm referring to:${F}_{G}=\frac{GMm}{{R}^{2}},$where M and m are the masses of objects.A logical explanation will be much appreciated.

Blaine Stein 2022-05-09

### Compare the gravitational attraction between objects on earth and interaction of celestial bodies in space. Which gravitational force is almost negligible? Why?

Jaime Coleman 2022-05-09

### Earth is the third planet in our solar system. If Earth became the fifth planet in our solar system, how would that affect the gravitationallforce? A. The gravitational force would increase. B. The gravitational force would decrease. C. The gravitational force would remain the same. D. The gravitational force would not change .

oglasnak9h01 2022-05-09

### I have heard that no one escape from the intense gravitational field of a black hole (obviously that's why it is black). And gravitational force is due to the mass having the body, no mass no gravity, as$F=GMm/{r}^{2}$Putting 0 in one of the two bodies' masses, gives no gravitational force. But light cannot escape from black hole due to its strong gravity, does that mean that light has mass? please correct me.

kwisangqaquqw3 2022-05-09

### What is the ratio of Earth’s gravitational force on a satellite when it is on the ground to the gravitational force exerted when the satellite is orbiting at an altitude of 890 km?

Paul Duran 2022-05-09

### Is time dilation due to relative velocity equivalent in principle to time dilation due to relative gravitational strength?Is time dilation due to relative velocity and relative gravitational strength equivalent? That is, similar to Einstein's thought experiment where an observer in an enclosed capsule with no windows cannot tell the difference between acceleration due to gravity or due to some applied force, is there any observable difference between time dilation due to velocity versus that due to gravity?

Jayla Faulkner 2022-05-09

2022-05-08

### From her bedroom window a women drops a set of keys to the ground 9m below.The keys are released from rest….how long are the keys in the air Find the speed of keys as they hit the ground

Peia6tvsr 2022-05-08

### Time period related to acceleration due to gravityThe period of a pendulum is given by$T=2\pi \sqrt{\frac{L}{g}}.$If we take a pendulum where there is no gravitational field, then $g=0$, therefore the period should become infinity. In such a condition what will our time relative to that of a person on earth will be? I believe that the time of a person will become too slow as it takes infinite time to complete one oscillation. Please tell me whether I am right or wrong, and if I am wrong please help me understand why.

poklanima5lqp3 2022-05-08

### The gravitational force between two objects is 2400 N. What will be the gravitational force between the objects if the mass of one object is doubled?

Edith Mayer 2022-05-08

### Why is $\frac{k}{4{\pi }^{2}}=\frac{c}{M}$ and $f=\left(kmM\right)/{r}^{2}$ not $\left(4{\pi }^{2}\right)/{r}^{2}\sqrt{MmcC}$?

Landon Mckinney 2022-05-08

### The sun has a mass 333,000 times that of the earth. For a person on earth, the average distance to the center of the sun is 23,500 times the distance to the center of the earth. In magnitude, what is the ratio of the sun's gravitational force on you to the earth's gravitational force on you?

Azzalictpdv 2022-05-08

### Suppose the gravitational force between two planets is 6,097 N. If the first planet was 2 times more massive and the second planet was 9 times more massive, what would be the gravitational force between them?

Marissa Singh 2022-05-08

### Acceleration due to gravity at CentreWhy is the acceleration due to gravity at the center of the earth $0$?My Attemptactually at the center distance from the surface is equal to the radius so the formula${g}^{\prime }=\left(1-\frac{d}{R}\right)×g$yields $0$.But can anyone give me the other reason for this?

Azzalictpdv 2022-05-08

### Acceleration due to gravityDoes acceleration due to gravity increase when an object at a said radius is doubled? Like for instance, if I said the radius of the earth is $5\phantom{\rule{thinmathspace}{0ex}}\mathrm{k}\mathrm{m}$ (not to scale obviously) if I doubled that, so $10\phantom{\rule{thinmathspace}{0ex}}\mathrm{k}\mathrm{m}$ will acceleration due to gravity double? Or maybe $g/2$? Or would the acceleration stay the same no matter distance?

Aedan Tyler 2022-05-08