Forces Flashcards
What is the difference between scalar and vector
Scalar - only have a magnitude
Vector - has a magnitude and a direction
What are examples of contact and non contact forces
Contact:
Tension
Friction
Air resistance
Non contact:
Magnetic
Electrostatic
Gravitational
What is the difference between weight and mass
Weight - the amount of force acting on an object
Mass - the amount of matter an object contains
What is the equation linking weight, mass, and gravitational field strength
W = mg
W - weight, measured in newtons (N)
m - mass, measured in kilograms (kg)
g - gravitational field strength, measured in newtons per kilogram (N/kg)
What is the equation linking work done, force and distance
W = Fs
W - work done, measured in joules (J)
F - force, measured in newtons (N)
s - distance, measured in metres (m)
What is Hooke’s law
The strain of the material is proportional to the applied stress within the elastic limit of that material
What is the equation linking force, spring constant and extension
F = ke
F - force, measured in newtons (N)
k - spring constant, measured in newtons per metre (N/m)
e - extension, measured in metres (m)
What is the limit of proportionality
The point beyond which Hooke’s law is no longer true when stretching a material
Required practical : How forces affect the extension of a spring
What is the method
Secure a clamp stand to the bench using a large mass on the base
Attach the spring to the top clamp and a ruler to the bottom clamp.
Adjust the ruler so that it is vertical, and with its zero level with the top of the spring
Measure and record the unloaded length of the spring
Hang a 100g mass carrier from the spring. Measure and record the new length of the spring
Add a 100 g slotted mass to the carrier. Measure and record the new length of the spring
Repeat until you have added a total of 1000g
What is the equation linking, speed, distance and time
s = vt
s - distance, measured in metres (m)
v - speed, measured in metres per second (m/s)
t - time, measured in seconds
What is the equation linking acceleration, change in velocity and time
a = ∆v / t
a - acceleration, measured in metres per second squared (m/s^2)
∆v - change in velocity, measured in metres per second (m/s)
t - time, measured in seconds
How do you read a distance time graph
Gradient increasing - speed increasing
Constant gradient - constant speed
Gradient decreasing - speed decreasing
No gradient - stationary
How do you read a velocity time graph
Positive gradient - increasing acceleration
No gradient - constant acceleration
Negative gradient - decreasing acceleration
No gradient (on x = 0) - stationary
How do you calculate displacement on a velocity time graph
Calculating the area underneath the line
What is terminal velocity
The maximum speed of an object when all forces acting on it are balanced
