Chapter 4 - Force, Mass, and Weight Flashcards
What is the equation of force?
Force = mass x acceleration
F = ma
What equations are associated with the motion of a trolley down a slope?
The equations of a trolley’s motions are:
- F = ma
- F = mg sin(θ) where m and g are mass and gravity respectively and theta is the angle of the slope.
What is the relationship between drag and speed?
Drag force is directly proportional to speed².
How do you calculate acceleration, considering drag force and terminal velocity?
Acceleration of free fall = (mg-D)/m, where m is mass, g is gravity and D is drag force.
Define a moment (and therefore the equation for a moment).
What equation applies to two objects in equilibrium about a pivot?
For objects in equilibrium about a pivot:
Sum of clockwise moments = Sum of anticlockwise.
Define torque.
Torque of a couple = one of the forces x perpendicular seperation between the forces
T = Fd
State the equation for pressure of a water column.
P = hpg, where h is the height of the column, p is the density of the liquid, and g is the acceleration of free fall.
State the equation of upthrust.
Upthrust = Axpg where A is area perpendicular to the upthrust force, x is the height of the the object, p is the density of the liquid and g is gravity.
List all of the mechanical forces.
The mechanical forces are:
- Weight, Force due to Gravity, and Mass.
- Friction, Force due to resistance between two object surfaces.
- Drag, Force due to Fluid/Air Resistance and surface area.
- Tension, Force within a stretched cable or rope.
- Upthrust, Upward Buoyancy Force due to being on a fluid.
- Normal Contact Force, Force due to an object resting against another object.
State the principle of moments.
Principle of Moments: For a body in rotational equilibrium, the sum of the anticlockwise moments around a point is the same as the sum of the clockwise moments.
Define Archimedes’ Principle.
Define an object’s centre of gravity.
Define a couple.
A couple is defined as:
