# Calculating Resultant Forces: Salt Deposition, Aircraft Loops, and Lorry Bends

• MorallyObtuse
In summary: F α rate of change of momentumThe Attempt at a Solutionb.) F α m/t(v - u)F α 12(8)F α 96 NAgain, there are some problems with your solution to part b. First of all, I think (but I am not sure) that you have written that the force is proportional to the rate of change of momentum, using the Greek letter alpha as a symbol for "proportional to." There are three problems with this:1. The symbol for proportional to is not the same as the symbol for alpha (even though they look quite similar when handwritten):\propto \, \, \
MorallyObtuse
Is a.) correct?
Great help is required in the other two.

## Homework Statement

a.) Fine salt is deposited from a negligible height at a rate of 12kgs-1 onto a conveyor belt moving at speed 8.0ms-1.Calculate the force required to keep the belt moving at this velocity.

b.) A small aircraft of mass 1200 kg which is flying horizontally at 150 ms-1 is taken into a vertical circular path of radius 500m and it is kept in this path until the aircraft makes a complete loop. If the pilot has a mass of 72kg, calculate the force exerted on him by the seat when the aircraft is top and bottom of the loop.
Clueless, much assistance needed here, please.
c.) A lorry of total mass 12000 kg enters a horizontal circular bend of radius 350 m at a constant speed of 45kmh-1.Calculate the magnitude and the direction of the resultant horizontal force acting on the lorry as it travels around the bend
b. Calculate the angle to which the road must be banked in order to provide the same resultant without the need to rely on friction.
Clueless, much assistance needed here, please.

## Homework Equations

a.) F α rate of change of momentum

## The Attempt at a Solution

a.) F α m/t(v - u)
F α 12(8)
F α 96 N

There are some problems with your solution to part a, although I think you probably got the right answer. First of all, I think (but I am not sure) that you have written that the force is proportional to the rate of change of momentum, using the Greek letter alpha as a symbol for "proportional to." There are three problems with this:

1. The symbol for proportional to is not the same as the symbol for alpha (even though they look quite similar when handwritten):

$$\propto \, \, \, \, \, \textrm{(proportional to)}$$

$$\alpha \, \, \, \, \, \textrm{(alpha)}$$​

2. Alpha doesn't show up well in the default font used on the forums, and it just ends up looking like the letter 'a' (which makes your post confusing).

3. F is not merely proportional to the rate of change of momentum, it is in fact exactly equal to it (Newton's 2nd Law). I.e. the constant of proportionality is just 1. So you should really write:

$$\textbf{F} = \frac{d\textbf{p}}{dt}$$​

As for your solution, if the rate of change of momentum is constant, then we can write

$$F = \frac{\Delta p}{\Delta t} = \frac{\Delta m}{\Delta t}v$$​

where the mass flow rate $\Delta m / \Delta t$ and the velocity v are both given in the problem. This is what your equations should say. I'm not sure what v and u mean in the equations you wrote, but it seems that you somehow plugged in the right numbers.

Yep, I meant proportional to. And thanks.

## What is the purpose of calculating resultant forces in salt deposition?

The purpose of calculating resultant forces in salt deposition is to determine the direction and magnitude of the force acting on a salt particle. This information can help in predicting the movement and settling patterns of salt deposits, which is important in industries such as mining and oil extraction.

## How can resultant forces affect aircraft loops?

Resultant forces can affect aircraft loops by causing changes in the direction and velocity of the aircraft. If the resultant force is not balanced, it can lead to instability and loss of control, potentially causing the aircraft to enter a loop or spiral.

## Why is it important to consider resultant forces in lorry bends?

Considering resultant forces in lorry bends is important because it helps in understanding the forces acting on the lorry and the road surface. This information is crucial for designing safe and efficient roads, as well as for ensuring the stability and control of the lorry while navigating bends.

## What factors can affect the calculation of resultant forces?

The calculation of resultant forces can be affected by factors such as the angle and direction of the force, the weight and mass of the object, and any other external forces acting on the object. The shape and surface area of the object can also play a role in the magnitude and direction of resultant forces.

## How can resultant forces be calculated?

Resultant forces can be calculated using vector addition, where the individual forces acting on an object are combined using mathematical formulas such as the Pythagorean theorem and trigonometric functions. Computer simulations and experiments can also be used to calculate resultant forces in real-world scenarios.

• Introductory Physics Homework Help
Replies
2
Views
727
• Introductory Physics Homework Help
Replies
9
Views
4K
• Introductory Physics Homework Help
Replies
7
Views
4K
• Introductory Physics Homework Help
Replies
6
Views
2K
• Introductory Physics Homework Help
Replies
24
Views
6K
• Introductory Physics Homework Help
Replies
25
Views
3K
• Introductory Physics Homework Help
Replies
5
Views
7K
• Introductory Physics Homework Help
Replies
3
Views
2K
• Introductory Physics Homework Help
Replies
7
Views
1K
• Introductory Physics Homework Help
Replies
14
Views
3K