After a tornado, a 0.50 -g drinking straw was found embedded \(4.5 \mathrm{cm}\) in a tree. Subsequent measurements showed that the tree exerted a stopping force of \(70 \mathrm{N}\) on the straw. What was the straw's speed?

One of the most fundamental concepts in physics is Newton's second law of motion. This law states that the force acting upon an object is equal to the mass of the object multiplied by its acceleration (\( F = ma \)). To put it simply, this means that heavier objects require more force to move the same distance as lighter objects, assuming the acceleration is constant.

In our exercise, this law helps to understand the force the tree exerted on the straw and how this force resulted in decelerating the straw. By measuring the force and knowing the mass, we can find out how quickly the straw decelerated. This understanding is crucial for solving problems related to objects in motion, whether they are speeding up or slowing down.

Deceleration is simply negative acceleration. When an object slows down, deceleration occurs, and it is a key concept in calculating changes in velocity over time. The importance of calculating deceleration correctly boils down to precisely understanding motion in reverse—a slowing force instead of an accelerating force.

In our exercise, deceleration is calculated by taking the force exerted on the object (the straw) and dividing it by the object's mass. The result is an acceleration value that is negative because it represents a force in the opposite direction of motion. Remember to treat the sign with care; in physics, a negative acceleration doesn't mean the absence of acceleration—it indicates a reduction in speed.

The equations of motion are a set of formulas that predict the future position and speed of an object moving under constant acceleration. They wonderfully relate distance, speed, acceleration, and time. One such equation is \(v^2 = u^2 + 2ad\), where \(v\) represents final velocity, \(u\) represents initial velocity, \(a\) is acceleration, and \(d\) is the distance moved.

In our tornado-struck straw scenario, we looked for the straw's initial speed before it hit the tree. By knowing the straw came to a stop (\(v = 0 m/s\)), we could use the equation of motion to solve for \(u\) knowing the deceleration and distance. These kinematic formulas are invaluable tools for physicists and engineers, encapsulating the laws of motion in a practical way for problem-solving.