Tagged Questions
-3
votes
0answers
36 views
A space vehicle travelling at a velocity of 1296 (km/h) separates by a controlled explosion into two sections of mass 7276 (kg) and 236 (kg) [closed]
A space vehicle traveling at a velocity of 1296 (km/h) separated by a controlled explosion into two sections of mass 7276 (kg) and 236 (kg). the two parts continue in the same direction with the ...
-2
votes
1answer
53 views
Why is there no such thing as a body in a state of acceleration?
It appears that velocity is a quantity of motion meaning that all objects can have assigned to them a particular velocity. Through the application of forces (ex: gravity, E&m) we measure changes ...
0
votes
0answers
13 views
Determining the acceleration of one to another with three unknowns [closed]
Given the following image, how would you determine the acceleration of block A, and the acceleration of block B relative to A? I'm trying to include the pulley as part of block A but I cannot figure ...
0
votes
3answers
91 views
Parachute in vacuum
Consider that the earth is vacuum. Consider a person of weight 100 kg is falling from sky with an parachute . He is free falling at height of 3000 m. When will he reach the ground? What would happen ...
0
votes
1answer
79 views
Kinematics with non constant acceleration
A particle experiences an acceleration described by
$$
a=kx^{-2}
$$
where x is the displacement from the origin and k is an arbitrary constant.
To what value does the velocity v of the particle ...
5
votes
2answers
240 views
Explanation that air drag is proportional to speed or square speed?
A falling object with no initial velocity with mass $m$ is influenced by a gravitational force $g$ and the drag (air resistance) which is proportional to the object's speed. By Newton´s laws this can ...
0
votes
3answers
114 views
Force with zero acceleration [duplicate]
If I apply a force on a body which is kept against a wall, then the body will not move. The body is not moving means that its velocity is zero, and hence its acceleration is also zero. According to ...
2
votes
2answers
97 views
Where are we : On level ground or on a ramp - moving in a train?
Let's say we are traveling in a train. The path has two parts: one at ground-level and the other moving up on the ramp. The ramp has an inclination of $\arctan\frac{a}{g}$ with the horizontal, where ...
5
votes
1answer
88 views
Aircraft nose-up glide
In the pilot's introductory book "Stick and Rudder" it claims that a nose-up glide is possible. It doesn't state how, why or when. It implies it's possible to do and maintain a constant forward ...
3
votes
1answer
103 views
Does a fly get brought up to speed with a bus?
Consider a scenario where a bus is moving at a constant speed and a fly enters through a window,the fly is also flying at a constant speed.
Since the bus is not in contact with the fly and neither is ...
6
votes
6answers
536 views
When driving uphill why can't I reach a velocity that I would have been able to maintain if I started with it?
Consider these two situations when driving on a long straight road uphill:
Starting at a high velocity $v_h$, which the car is able to maintain.
Starting at a lower velocity $v_l$, and then trying ...
6
votes
8answers
478 views
Can you completely explain acceleration to me?
I understand what acceleration is, and I know the formula, and I understand it's a vector.
I just don't understand how the equation works exactly. I'm kind of picky, I know, but bear with me.
...
7
votes
5answers
430 views
How can kinetic energy be proportional to the square of velocity, when velocity is relative?
Let's start with kinetic energy (from los Wikipedias)
The kinetic energy of an object is the energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a ...
0
votes
1answer
328 views
Relative Velocity and Momentum
The question is, "A $45.5~kg$ girl is standing on a $140~kg$ plank. Both originally at rest on a frozen lake that constitutes a friction-less, flat surface. The girl begins to walk along the plank at ...
1
vote
1answer
125 views
How much runway does the space shuttle need to land?
A textbook question proposes the following scenario:
NASA needs to plan emergency landing sites for the Space Shuttle (RIP). There are a number of things to consider. The shuttle touches down no ...
-1
votes
1answer
247 views
How does Baumgartner slow his velocity so that the parachute can open up?
How does Baumgartner slow his velocity so that the parachute can open up?
What is Baumgartner's speed just before his parachute opens?
What causes his speed to slow down just before the chute opens?
...
2
votes
4answers
874 views
Physics behind Wheel Slipping
Lets say that I'm in a car and I apply full acceleration suddenly. Now, the wheels would slip and hence the car doesn't displace much.
But If I start with some constant acceleration, slipping doesn't ...
0
votes
0answers
74 views
Jumping on a landing pad [closed]
I'm trying to make a character jump on a landing pad who stays above him. Here is the formula I've used (everything is pretty much self-explainable, maybe except character_MaxForce that is the total ...
2
votes
0answers
129 views
2D Car Physics including Throttle
For a simulation for testing on automatic cruise control, I came across the equation:
$$
v_{n+1} = (1 - k_1 / m) v_n + (1 - k_b) \begin{pmatrix}
T_n \\
θ_n \\
\end{pmatrix}
$$
where:
$T$ = ...
2
votes
2answers
240 views
Lever Mechanics - How to formulate an ideal lever launch
Let's say I have a simple lever as shown below, and the lever is massless and the pivot is frictionless and there is no air resistance. I'm thinking the cradle for the projectile would have to have a ...
3
votes
2answers
604 views
How can an object's instantaneous speed be zero and it's instantaneous acceleration be nonzero?
I'm studying for my upcoming physics course and ran across this concept - I'd love an explanation.
-1
votes
1answer
127 views
What is the quantity in physics that is advanced from speed? [closed]
What is the quantity in physics that is advance from speed?
i know one is velocity, one is speed, one is acceleration.
1
vote
1answer
118 views
Determining Orbital Velocity
Is there any way to determine the orbital velocity of a point around another stationary point, if I don't know the mass of either of the points but know the force that gravity exerts and the distance ...
2
votes
4answers
535 views
How long must escape velocity be maintained?
Escape velocity from Earth's surface is 11.2 Kilometres/second
How long would one need to maintain this escape velocity to actually escape Earth's gravitational pull? Must this 11.2 km/s velocity ...
0
votes
2answers
459 views
What will be the relative speed of the fly? [duplicate]
It has happened many times and i have ignored it everytime.
Yesterday it happened again .
I was travelling in a train and saw a fly (insect) flying near my seat.
Train was running at a speed of ...
2
votes
3answers
251 views
Train crash: are these situations alike?
I was just wondering... I believe that if a car travelling 50 miles per hour crashes into a wall, the result should be the same as crashing to another car also travelling 50 miles per hour (but in the ...
2
votes
2answers
463 views
Velocity of Voyager 1
I was reading Wikipedia which stated
....Voyager 1's current relative velocity is 17.062 km/s, or 61,452 kilometres per hour (38,185 mph).....
It travels away from sun. So sun's gravity must ...
2
votes
3answers
830 views
What is terminal velocity?
What is terminal velocity? I've heard the term especially when the Discovery Channel is covering something about sky diving. Also, it is commonly known that HALO (Hi-Altitude, Lo-Opening) infantry ...
