Physics 1 - Work, Energy and Power Flashcards
1.2P List the units and unit symbols for: moments
Newton Metre (Nm)
1.2P List the units and unit symbols for: momentum
Kilogram metre per second (kg m/s)
1.3 Plot a distance-time graph for the following motion: stationary, constant speed, acceleration, deceleration
SEE ONENOTE Stationary - horizontal line Constant speed - straight line Acceleration - gradient increasing Deceleration - gradient decreasing
1.3 Describe how speed can be determined from a distance-time graph
Find the gradient
Average speed
Change in distance/change in time
1.4 Write down another equation for average speed if acceleration is constant in words and symbols
average speed=1/2(initial speed+final speed)
1.5 Practical: Describe a generic experiment to determine the average speed of an object
Get a set distance and measure it (ruler, tape measure, trundle wheel)
State how you will measure the time (stopwatch, light gates etc)
State the method (self explanatory)
Repeat, remove anomalies and take an average
Calculate the average speed
1.7 Plot a velocity-time graph for the following motion: stationary, constant speed, acceleration, deceleration
Stationary - Horizontal line on zero
Constant speed - horizontal line
Acceleration - Straight diagonal line going upwards
Deceleration - Straight diagonal line going downwards
1.8 Describe how acceleration can be determined from a velocity-time graph
Calculate the gradient
1.9 Describe how distance/displacement travelled can be determined from a velocity-time graph
Calculate the area from the x axis to the line.
Above the axis is a positive displacement, vice versa.
1.10 Write down the equation relating final speed, initial speed, acceleration and distance moved in words and symbols
Final speed squared = initial speed squared + (2 x acceleration x distance)
v^2 = u^2 + 2as
1.11 Describe the possible effects of forces between bodies
Change speed, shape or direction
1.13 State how a vector quantity is different from a scalar quantity
A scalar has only magnitude, a vector has magnitude and direction
1.15 Describe how to calculate the resultant force of several forces acting along a line
Choose one direction to be positive and the other negative. Add the quantities together using the signs used
Is force a scalar or vector?
Vector
1.16 Define friction
A force that opposes motion
1.17 Write down the relationship between unbalanced forces, mass and acceleration in words and symbols
Resultant force = mass x acceleration
∑F=ma
1.19 Define the thinking distance and braking distance
Thinking distance: distance travelled between spotting the hazard and pressing the brakes
Braking distance: distance travelled between pressing the break and coming to a complete stop
1.19 Define stopping distance
Thinking distance + braking distance
1.20 Describe and explain the factors that affect thinking distance
Speed - travel further in the same amount of time
Reaction time - affected by alcohol, tiredness, distraction from phone
1.20 Describe and explain the factors that affect braking distance
Mass - increases momentum and KE
Road/car conditions - reduces braking force
Speed - has greater kinetic energy so takes longer to come to a complete stop
1.21 Describe and sketch the forces acting on a falling object
Weight - downwards
Drag/air resistance/friction - upwards (smaller)
1.21 Define terminal velocity and sketch a diagram
Forces reach equilibrium - drag = weight
Therefore the object travels at a constant speed
- 22 Practical: Design an experiment to investigate how extension varies with applied force for
a. Helical springs
b. Metal wire
c. Rubber band
Set up a clamp, attached to the table by another clamp, with a ruler set upnext to a spring.
Measure the initial length of the spring, then add different masses (IV) and measure the extension (DV)
Accuracy - make sure the ruler is close to avoid a parallax error. Repeat the experiment and calculate an average extension
Plot a force extension graph; put a straight line through it - the gradient is the spring constant.
Wire: do the same but use a micrometre
Rubber band: measure the extension as masses are removed to show the hysteresis in the graph