26
votes
5answers
4k views

Which ball touches the ground first?

This is a very well known problem, but I can't find an answer in the specific case I'm looking for. Let's consider two balls : Ball 1 weighs 10 kg Ball 2 weighs 1 kg Balls have identical volumes ...
1
vote
0answers
44 views

Freely Falling Bar in a Magnetic Field

I have a horizontal bar on vertical rails and we can consider that does not exist any friction. Perpendicular to the plane of the rails it exists a magnetic field $B$. I am asked to find the ...
1
vote
1answer
79 views

Trajectory of falling object, with and without initial velocity

If an object is dropped from a roof with no initial velocity and wind is blowing along the side of the building exerting a constant force on the object, then its trajectory will be a straight line. ...
-1
votes
2answers
44 views

Free fall question: Bill shoots his gun [closed]

Bill borrows his dad's gun and when he gets outside he fires it straight up into the air. If the bullet left the gun at 400 m/s: How long does it take the bullet to reach its highest point. I know ...
0
votes
0answers
59 views

Free fall from space [duplicate]

If you leave a ball weighing 10 kg at a height of 500 km above sea level (neglecting air friction). How can calculate how long the ball hits the ground and what will be its speed? I know that: On ...
-1
votes
1answer
137 views

free falling object with air resistance?

we already know that if we plot speed vs time of free falling object it will be y=gx graph because we know the acceleration is gravity. If it have air-resistance acceleration will be change right?. ...
1
vote
1answer
71 views

Calculating the height objects fall from [duplicate]

Imagine an object of a given mass. The object falls from a certain height. On contact with the ground, the object has a certain force. If the force of the object and the mass of the object are ...
0
votes
1answer
90 views

How to obtain the distance traversed by a free falling body equation?

I know that the distance that a free falling body has traverse through time is given by $d=0.5*g*t^2$. I would like to know how to get to this equation to study a bit more how it was obtained. I have ...
-5
votes
1answer
78 views

Ascertain the height an object has fallen from given force exerted and mass [closed]

An object of a given mass falls from an unknown height. If the force exerted by the object on contact with the ground is known, how would you ascertain the height from which the object fell?
1
vote
2answers
220 views

Force on carabiner from free fall [closed]

Suppose I weigh about $75~\text{kg}$ and I am attached to a (non-elastic) rope which is attached to a carabiner which can take at least $20~\text{kN}$. Suppose furthermore that I reach terminal ...
0
votes
1answer
129 views

Question about weightlessness

Let us consider +Y as upward and -Y axis as downward. So the acceleration that works these objects is always $-g$. For the first picture, if the lift is going upward with acceleration $a$, then ...
3
votes
1answer
241 views

How deep is the well, given this data?

A rock is dropped into a well. A timer starts when the rock is dropped and is stopped when the noise of the rock hitting the ground of the well is heard. How deep is the well? Here's what I have so ...
0
votes
0answers
93 views

Using thermodynamics and Kinematics together to solve a parachuter problem?

I need to find a parachutist's displacement after a given height (nearly 37000m) and at a given latitude. I have his mass, area, parachute area, drop height, parachute deployment height, data about ...
0
votes
1answer
593 views

Time taken for object in space to fall to earth

The Problem For a small mass a distance $R_i$ away from the center of the Earth, how long would it take for the object to fall to the surface of the Earth, assuming that the only force acting upon the ...
3
votes
4answers
11k views

Calculating impact force for a falling object?

Good evening, I'm trying to calculate what kind of impact force a falling object would have once it hit something. This is my attempt so far: Because $x= \frac{1}{2} at^2$, $t=\sqrt{2x/a}$ $v=at$, ...
1
vote
1answer
212 views

How do I factor in multiple forces into these Newtonian mechanics equations?

Say a person is walking along. He then jumps. The person weighs $25$kg (irrelevant?). Just after jumping, his velocity is 5m/s (positive is taken as up). Gravity is taken as ...
1
vote
1answer
1k views

Trajectory of projectile thrown downhill

I'm teaching myself mechanics, and set out to solve a problem determining the optimum angle to throw a projectile when standing on a hill, for maximum range. My answer seems almost plausible, except ...
0
votes
1answer
310 views

Calculating the launch angle of a horizontal launch (mechanics) [closed]

I need some help with the following question: A smooth spherical object (the first object) is projected horizontally from a point of vertical height H = 26.38 metres above horizontal ground with a ...
3
votes
3answers
541 views

A freefalling body problem, only partial distance and time known

Well, I've been trying to figure out a problem which I imposed on myself, so no literal values included. Unfortunately, my brain is not cooperating. The problem states: What is the height from ...
7
votes
2answers
402 views

Equivalence principle and radiation from falling particle

I am currently having a hard time solving a problem of GR from Lasenby's book. I can't make it more clear than by quoting the exercise: 7.2 A charged object held stationary in a laboratory on the ...
0
votes
2answers
699 views

Basic Free Fall Problem [closed]

So I am trying to remember my childhood doing some Physics problems, but seems that I forgot almost everything. But it's not a big thing... that's why I'm training! My problem is pretty basic ...