General Physics - Force and Energy

Fill-in-the-blank practice flashcards covering Chapter 1: Force and Energy, including types of forces, static equilibrium, biomechanics, work, energy, power, and metabolic rates.

A force is defined as the influence that changes or tries to change the __________ of objects.

states of motion

A force is a vector quantity, which means it is characterized by both __________ and direction.

magnitude

For an object to be in equilibrium, the vector sum of all forces acting on the object must equal __________.

$$0$$

The weight force $W$ of a body is directed towards the __________ of the earth.

center

The downward attraction force due to gravity on Earth is calculated as $F_W = m \times$ __________.

$$9.8$$

When a block rests on a table, the table exerts an upward action force called the __________ force that balances its weight.

normal

The friction force opposes the sliding of a body on a surface and is always __________ to the contact surface.

parallel

If a force applied to a block does not move it, the balanced opposing force is static friction given by $F_s =$ __________.

$$\mu_s N$$

When an applied force causes a block to slide, the frictional force becomes dynamic friction, defined by $F_k =$ __________.

$$\mu_k N$$

For a $10\,kg$ block pulled at constant velocity by a $50\,N$ force at an angle of $25^\circ$, the coefficient of kinetic friction $\mu_k$ is __________.

$$0.59$$

When a rope or cable is attached to a body and pulled, it is said to be in tension, usually denoted by the symbol __________.

$$T$$

In traction with a suspended mass of $5\,kg$ and angle $\theta = 20^\circ$, the net tension force on the leg is calculated to be __________ $N$.

$$92.09$$

The study of how muscle forces act to produce human motion and balance is known as __________.

biomechanics

A skeletal muscle is typically connected to two different bones at either end by flexible bands called __________.

tendons

Torque ($\tau$) is a physical quantity associated with the ability of a force to produce __________ about an axis.

rotation

The moment of rotation or torque depends on the perpendicular distance $r_\perp$ and applied force $F$, defined as $\tau =$ __________.

$$r_\perp F$$

A body is in static equilibrium only when $\sum F_x = 0$, $\sum F_y = 0$, and __________ $= 0$.

$$\sum \tau$$

In the horizontal forearm model shown holding a $50\,N$ sphere, the upward force exerted by the biceps $F$ is __________ $N$.

$$583$$

In the forearm model holding a $50\,N$ sphere with biceps force $F = 583\,N$, the downward force $R$ exerted at the elbow joint is __________ $N$.

$$533$$

In the push-up diagram shown for a person weighing $700\,N$, the vertical reaction force $H$ exerted by the floor on the hands is __________ $N$.

$$437.5$$

In the push-up scenario with a total body weight of $700\,N$ and a hand force of $437.5\,N$, the upward force $F$ at the feet is __________ $N$.

$$262.5$$

Work occurs whenever a force is applied to an object and causes __________ of the object by that force.

movement

In cgs units, the unit of work is dyne-centimeter, which is abbreviated as __________.

erg

The conversion between SI and cgs units of work is $1\,J =$ __________ ergs.

$$10^7$$

The kinetic energy $K$ of an object with mass $m$ moving at speed $v$ is defined as $K =$ __________.

$$\frac{1}{2}mv^2$$

The gravitational potential energy required to lift an object of mass $m$ through a vertical distance $h$ is $P.E =$ __________.

$$mgh$$

Power is defined as the time rate at which __________ is being done.

work

The SI unit of power is Joule per second ($J/s$), which is called a __________.

Watt

One horsepower ($1\,hp$) is equivalent to __________ Watts.

$$746$$

When an applied force $F$ moves an object at a constant velocity $v$, power is given by the formula $P =$ __________.

$$Fv$$

The lowest rate of energy consumption under resting conditions needed to perform minimal body functions is the __________.

basal metabolic rate

If human body temperature changes by $1\,^\circ C$, the metabolic rate changes by __________.

$$10\%$$

Under resting conditions, approximately __________ of the body's energy consumption is utilized by skeletal muscles.

$$25\%$$

Under resting conditions, approximately __________ of the body's energy consumption is used by the brain.

$$19\%$$

Under resting conditions, the liver and spleen consume approximately __________ of the body's total energy.

$$27\%$$

The efficiency ($\eta$) of the human body is calculated as $\eta = \frac{\text{work done}}{\text{Total energy consumed}} \times$ __________.

$$100\%$$

According to Hill's law of muscular power, the power output of a muscle depends directly on its __________.

cross-sectional area

A horse with a power output of $1\,kW$ pulling a wagon with a force of $400\,N$ moves at a velocity of __________ $m/s$.

$$2.5$$

A motor boat requiring $60\,kW$ to maintain a constant speed of $4.5\,m/s$ experiences a resistive water force of __________ $N$.

$$1.33 \times 10^4$$

A $1\,kg$ object with a kinetic energy of $1\,J$ moves with a velocity of __________ $m/s$.

$$1.4$$