Chapter 4: Force and Motion

Flashcards covering fundamental concepts of force and motion from Chapter 4 of University Physics for the Life Sciences, including Newton's first and second laws, free-body diagrams, and vector component calculations.

Kinematics and dynamics together form the general science of motion, known as __________.

mechanics

While kinematics describes motion using pictures, graphs, and equations, the branch of mechanics that focuses on the causes of motion is called __________.

dynamics

An object's resistance to change—its tendency to stay at rest or keep moving in a straight line at constant speed—is called __________.

inertia

According to Newton's first law, an object with no forces acting on it that is already moving will continue to move in a straight line at a __________ speed.

constant

Every force is a push or a pull, acts on an object, is a vector, and requires a(n) __________, which is something that pushes or pulls.

agent

Forces are categorized broadly into two classes: contact forces and __________ forces.

long-range

When drawing a force vector according to Tactics Box 4.1, the object is represented as a particle, and the __________ of the force vector is placed on that particle.

tail

Ignoring air resistance, the only force acting on the ball just after it leaves the horizontal ramp is __________.

the weight of the ball acting vertically down

For a steel beam hanging from a cable as a crane lifts it, the only forces acting on the beam are gravity and __________.

tension in the cable

Just after a bobsledder pushes her sled across horizontal snow and jumps inside, the three forces acting on the slowing sled are gravity, kinetic friction, and a(n) __________.

normal force

As shown in the experimental graph for a glider of constant mass, an object's acceleration is directly proportional to the __________ acting on it.

force

When pulled by a constant tension force, a $1.0\,\text{kg}$ glider accelerates at $3.0\,\text{m/s}^2$. A second glider pulled with the identical tension accelerates at $5.0\,\text{m/s}^2$, which means the mass of the second glider is __________.

$$0.60\,\text{kg}$$

Newton's second law states that the acceleration of an object is directly proportional to the net force and inversely proportional to the __________.

mass

When an object suspended by a rope is lowered at a constant speed, the rope tension __________ the object's weight.

equals

When an object on a rope is lowered at a steadily decreasing speed, the acceleration vector points upward, meaning the rope tension is __________ than the object's weight.

greater

When dropping a basketball in a stiff breeze blowing to the right, the ball accelerates in the direction of the net force, which points __________.

downward and to the right

If a constant net force causes an object to accelerate at $4\,\text{m/s}^2$, an object with twice the mass subject to the exact same net force will accelerate at __________.

$$2\,\text{m/s}^2$$

A $51,000\,\text{kg}$ Boeing 737 reaches a takeoff speed of $70\,\text{m/s}$ after accelerating uniformly across $940\,\text{m}$; the thrust required from each of its two engines is __________.

$$67\,\text{kN}$$

In a free-body diagram for an elevator speeding up as it travels upward, the upward tension vector is drawn __________ than the downward weight vector.

longer

An elevator suspended by a cable is moving upward and slowing down; its net force points downward, which means the upward cable tension is __________ than its weight.

less

Unlike the scalar components of a vector that can be positive or negative, the magnitude of a vector can never be a __________ number.

negative

Based on the coordinate axes shown, the $x$- and $y$-components of this vector are __________.

$$3, -4$$

For the displacement vector $\vec{C}$ extending from $(1\,\text{cm}, -1\,\text{cm})$ to $(-3\,\text{cm}, 1\,\text{cm})$, its components are $C_x = -4\,\text{cm}$ and $C_y = \_\_\_\_\_\_\_\_\_\_$.

$$2\,\text{cm}$$

For a vector with magnitude $A$ oriented at an angle $\theta$ relative to the horizontal, its components are given by $A_x = A\cos(\theta)$ and $A_y = \_\_\_\_\_\_\_\_\_\_$.

$$A\sin(\theta)$$

Given components $A_x$ and $A_y$, the magnitude of vector $\vec{A}$ is calculated using the Pythagorean expression $A = \_\_\_\_\_\_\_\_\_\_$.

$$\sqrt{A_x^2 + A_y^2}$$

When working with Newton's second law in two dimensions, the vector equation resolves into the two component equations $F_{\text{net},x} = ma_x$ and $F_{\text{net},y} = \_\_\_\_\_\_\_\_\_\_$.

$$ma_y$$

The three systematic phases of the Newtonian mechanics problem-solving strategy are Prepare, Solve, and __________.

Assess