When a small car and a large truck have a head-on collision, what is true about the forces they exert on each other?
They exert equal and opposite forces on each other.
In which situation are unbalanced forces acting on an object?
Unbalanced forces act when an object is accelerating or changing its state of motion.
Why is force considered a vector quantity?
Force is a vector because it has both magnitude and direction.
The forward force produced by the engines of an aircraft is an example of which type of force?
It is an example of an applied force (thrust).
What is an example of a non-contact force?
Gravity is an example of a non-contact force.
When a nail is hit with a hammer, which type of contact force is applied?
An applied force is exerted by the hammer on the nail.
What factor commonly causes the most collisions in everyday life?
Unbalanced forces, such as sudden applied forces or loss of friction, commonly cause collisions.
Extension of the arm at the elbow is an example of what type of lever system?
It is an example of a third-class lever system.
Which force is a non-contact force?
Weight (gravity) is a non-contact force.
What does a free-body diagram of a truss member in equilibrium show?
It shows all the forces acting on the member, with arrows indicating their directions and relative magnitudes, and the net force is zero.
What type of lever has resistance between the axis (fulcrum) and the force (effort)?
A second-class lever has the resistance (load) between the fulcrum and the effort.
Which of the following is not a component of a lever: effort, tension, fulcrum, or load?
Tension is not a component of a lever; the main components are effort, fulcrum, and load.
What type of force does a backpack exert on the body's back and hips?
A backpack exerts a normal force on the body's back and hips.
Which two factors does the power of a machine depend on?
The power of a machine depends on the amount of work done and the time taken to do it.
Teeth are an example of which type of simple machine?
Teeth are an example of a wedge, a type of simple machine.
What best describes a non-contact force?
A non-contact force acts on an object without physical contact, such as gravity.
What change to a wire would cause its resistance to decrease?
Increasing the wire's thickness (cross-sectional area) or decreasing its length would decrease its resistance.
What is the purpose of a free body diagram?
A free body diagram helps visualize and organize all the forces acting on a single object.
What are the forces acting on a stationary object resting on a surface?
The weight force acts downward and the normal force from the surface acts upward.
Tensional forces normally cause which effect on a material?
Tensional forces cause a material to stretch or elongate.
What are four main factors that contribute to the majority of collisions?
Unbalanced forces, loss of friction, sudden applied forces, and failure to maintain control contribute to most collisions.
What is the force that acts perpendicular to a surface due to contact?
The normal force acts perpendicular to a surface due to contact.
How do you determine the net force acting on an object using a free-body diagram?
Sum all the forces acting on the object, taking their directions into account; the result is the net force.
How do you label devices in a simple circuit diagram?
Label the bulb as the light source, the switch as the control, and the battery as the power source.
What are tools that give the user a mechanical advantage called?
They are called simple machines.
What is an example of a pulling force?
Tension in a rope when pulling a sled is an example of a pulling force.
What are the contact forces exerted on a crate resting on the ground?
The normal force from the ground and friction force (if there is any attempt to move the crate) are contact forces.
What happens when two couples (pairs of equal and opposite forces) act on a beam?
The beam experiences rotational effects depending on the magnitude and direction of the couples.
How do you determine if a truss member is in tension or compression?
If the member is being pulled apart, it is in tension; if it is being pushed together, it is in compression.
How do you identify which forces act on a car?
Identify all forces such as weight, normal force, friction, and any applied forces acting on the car.
How do you identify the forces acting on a baseball player?
Consider the weight force, normal force from the ground, friction, and any applied forces (such as from running or hitting).
What forces act on a skydiver-parachute system?
The weight force acts downward, and air resistance (a type of friction) acts upward.
How do you draw a free-body diagram for a beam with a rocker at point A and a pin at point B?
Draw the beam as a line, show the reaction force at the rocker (vertical only) at A, and both vertical and horizontal reaction forces at the pin at B, along with any applied loads.