1. ### I Heavier objects fall faster?

I remember being told that heavier things fall at the same rate as lighter things when everything else is equal. But this guy does a demonstration of a Xenon balloon falling faster than a Neon balloon. Why??? Also an overloaded plane may not be able to fly, but it has the same aero dynamics...
2. ### Block on a slope with a weight

This is my attempt of solving it

4. ### Pulling with and without a pulley

Let me draw a free body diagram for the man. I assume that for both cases (a) and (b), the man pulls the block up with uniform velocity. (1) In case (a), realising that the man is in equlibrium (##\Sigma F = 0##) the normal reaction on the man ##N_a = w_M + T## is given by ##N_a = (50+25)\times...
5. ### How much force does a moving car exert on to the road?

I understand that the weight of the car does not change (assuming mass of the car stays the same) because of f=mg. But I am not so sure about of the aerodynamics of the car plays a role. Say, a faster car might have more air under their wheels and might exert less force on to the ground. Maybe a...
6. ### Weight of water with objects floating

We understand that the crucial thing about the problem is that the volume of water present in the three containers are not the same. Also, we note that in each case the weight of the container is the total weight of its contents. (A student might be confused as to why should be so - after all...
7. ### B Reduction in Apparent weight

When a body accelerates down(climbs down) a rope, why does its apparent weight reduce? Oh wait, does it even reduce in the first case? If yes, is it because of the newtons first law of motion, which states that a body in motion tends to be in motion and a body at rest tends to be at rest. So...
8. ### Sphere and Bar in freefall

For convenience, I have marked the C.G. of the sphere as ##G_S## and that of the bar only as ##G_B##. The C.G. of the combination is halfway between them, shown by the green ##G_C##. My answer is that the combination will rotate about ##G_C## (centre of the bar) as it falls. I wonder if I am...
9. ### Mechanics of Solids - weight problem

Summary: How much weight can the bars support? Three one-meter-long bars with cross-section area A = 1 square centimeter support a rigid plate of weight W. For steel, E = 200 GPa and S = 400 MPa. Determine the maximum weight W the bars can support for three cases: (i) all three bars are...
10. ### I Gram as weight?

Ok so I've asked my physics teacher and a statics teacher as well and I couldn't get a straight answer from either. So here's my questions... Correct me if i'm wrong, but isn't the gram a unit of mass? Not weight? I thought that for mass to become a unit of weight, it has to have to...
11. ### What is the minimum force at this angle that will move the box?

Homework Statement [/B] 2. Homework Equations Fs = Nμ W = mg Fy = Fsin(θ) Fx = Fcos(θ) The Attempt at a Solution [/B] Hello all at PhysicsForums, I have a question on angled force and static friction. From my attempt below, I think I have found the maximum force required and would need...
12. ### B Measuring the weight of gas in an inflated balloon

What could be the method for measuring weight of gas in inflated balloon? Thanks & Regards, Prashant S Akerkar
13. ### Effect of zero gravity on spinal compression

I am trying to compare an experiment on spinal changes due to zero-g in astronauts. Researchers simulated zero-g spinal elongation by suspending human subjects so that no part of their body touched the ground. This figure shows the % change in disc thickness for each subject compared to data...
14. ### Finding the change in weight from the force & difference in height (y)

Information Given:In 1956, Frank Lloyd Wright proposed the construction of a mile-high building in Chicago. Suppose the building had been constructed. Question: Ignoring Earth's rotation, find the change in your weight if you were to ride an elevator from the street level, where you weigh 708...
15. ### B Difference between "1 kgf" and "1 N"?

What is the difference between 1 kgf and 1 Newton?
16. ### Newton's 3rd Law (Pulleys - 1)

Hi, I'm new here. Could someone provide some guidance on how to start this problem?
17. ### Apparent Weight Problem

Homework Statement What is the apparent weight of a 70-kg astronaut 3800 km from the center of the Earth's Moon in a space vehicle when a) Moving at a constant velocity b) Accelerating toward the Moon at 2.9 m/s^2? State direction in each case Homework Equations wt = m(g+a) wt = m(g-a) Fgr =...
18. ### I Can a bicycle be tipped over by only applying rear brake?

Let's say I'm riding a bike at constant speed. Also assume that the person riding is rigid, no moving of the persons body, constant center of gravity. Assuming that there is sufficient friction between the tires and road. If I apply the front brakes, I will likely tip over. If I apply the...
19. ### Automotive How to find the uneven weight distribution on 4 wheels

Hello, I am working on a project where I am trying to find the weight distribution on a 4 wheeled vehicle that is traveling diagonally up an incline. You can effectively think of the vehicle as having a pitch and a yaw angle in the body frame. Using an arbitrary location of the total center of...
20. ### B Force (in lbs) to speed?

Hello, I have been looking at physics calculators, but cannot seem to find precisely what I need. I don't need a very precise answer, merely a realistic ballpark one. I need to know how we find the rough speed of an object's movement when a certain amount of force is applied to it. For...
21. C

### Finding torque by integration of weight

Homework Statement Hi. I ve got a problem, where I have to show torque by integrating the weight of the rod over the whole it's length. Homework Equations [/B] Result, what I am suppose to get is: ## \tau_{rod} = \frac{mgb}2 ## The Attempt at a Solution [/B] When I try to integrate, Im...
22. B

### Automotive How does a weight distributing hitch help towing capacity?

Most hitches are rated as "X, 0.1*X weight-bearing, Y, 0.1*Y weight-distributing" where Y > X and the first number is trailer weight, second number is tongue weight. It has been described to me many times that the weight distributing hitch (with 'stabilizing/leveling' bars) "takes weight off...
23. J

### B Does someone weigh more on a steel ship?

Say you were on a steel ship, standing on very thick steel. Would you technically weigh more? Would the gravity pull you down more?
24. ### Concrete Slab Thickness

Good morning forum, I'm currently in the middle of a project where I'm installing a new chemical storage tank outside. I need to lay a new concrete slab for the tank to lay on. My question is how thick should the concrete slab be? The tank will be stationary, when filled it will weigh...
25. A

### Weight of a person a certain distance above the Earth

Homework Statement The problem is stated in the picture. Homework Equations Fg=Gm.1m.2/r^2 The Attempt at a Solution I found a similar question where someone wanted to find how high will the weight be half the weight on the surface. Here is one of the answers: F =G.m1.m2/r^2 F´ =G.m1.m2/r´^2...
26. ### How does the gradient of the graph compare to the W force

Homework Statement How does the gradient of the graph compare to the weight force? The graph is a Mass vs 1/Acceleration graph (y axis = mass, x axis = Acceleration, It was mentioned to do this.) Homework Equations Explain by referring to the formula for Newton's Second Law. The Attempt at a...
27. ### Statistical weighting of data to improve fitting

Homework Statement I am trying to perform a weighted fit of a data set ##(x,y)## shown below. The only information I have are the two vectors ##x## and ##y## and the uncertainty present in the ##y## values (##=0.001##). Homework Equations The Attempt at a Solution Statistical weighting of...
28. ### B Can a magnet have more push force than it weighs?

Simple question. Can a magnet have more push force than the magnet itself weighs. Example: A magnet weighing 2kg having a push force equal to 3kg.
29. ### How to find Torque without Coefficient of Friction?

Hello! I am an AP Physics student and had a quick question for validity. I was prompted with this question in class today: Example 7: An 8-meter ladder of weight 355 N leans at an angle of 50° to the floor against a smooth vertical wall. Assume the center of weight (gravity) for the ladder is at...
30. ### What would happen to the ball?

Homework Statement Assume that the beaker is half filled with Hg, the steel ball being lighter will float in it half-submerged. Now we pour water into the beaker, so that the beaker is completely filled with water on top, Hg in the bottom and steel ball floating between them. Now my question...