# A couple of problems on motion and force

• Gauss177
In summary, a flatbed truck carrying a 3200-kg crate with a coefficient of static friction of 0.65 can decelerate at a maximum rate of 20384 N to avoid crushing the cab with the crate. The maximum frictional force can be found by using Newton's Second Law and the minimum stopping distance can be calculated by finding the maximum decelerating force using the same equation.
Gauss177

## Homework Statement

A flatbed truck is carrying a 3200-kg crate of heavy machinery. If the coefficient of static friction between the create and the bed of the truck is 0.65, what is the maximum rate at which the driver can decelerate when coming to a stop in order to avoid crushing the cab with the crate?

fric = u*N
Fnet = m * a

## The Attempt at a Solution

N = 3200*9.8 = 31360
fric = 0.65 * 31360 = 20384 N

thats as far as I got

Last edited:
thechuckisback said:
fricc= u*N*d*e I think

What are d and e? The frictional force is equal to the coefficient of friction, mu, times the normal force which is usually denoted by N.

For 1), use Newton's 2nd law, F = ma. F is the decelerating force and the same force F acts on both the truck and the crate. But the actual force that slows down the crate is the force of friction between the crate and the floor of the truck. So what is the maximum frictional force you can have ?

2) is similar. Use F = ma and Fr = μm to get a. And minimum stopping distance comes from maximum decelerating (frictional) force.

## 1. What is the difference between motion and force?

Motion refers to the movement of an object or body, while force is the push or pull that causes an object to move or change its state of motion. In other words, motion is the result of force acting on an object.

## 2. How are motion and force related?

Motion and force are directly related to each other. Force causes an object to move or change its motion, and the motion of an object can also create a force. This relationship is described by Newton's Second Law of Motion, which states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

## 3. What are the different types of motion?

There are three main types of motion: linear motion, rotational motion, and oscillatory motion. Linear motion is when an object moves in a straight line, rotational motion is when an object spins around a fixed axis, and oscillatory motion is when an object moves back and forth repeatedly.

## 4. What factors affect an object's motion?

An object's motion is affected by several factors, including the amount and direction of the force applied, the object's mass, and the surface it is moving on. Other factors such as air resistance, friction, and gravity can also play a role in an object's motion.

## 5. How can we measure motion and force?

Motion can be measured using various tools such as a ruler, stopwatch, or motion sensors. Force can be measured using a spring scale, force meter, or dynamometer. In order to accurately measure motion and force, it is important to use the appropriate tools and units of measurement.

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