Topic 2 - Forces And Motion Flashcards
What is a vector?
A quantity with both magnitude (size) and direction
What is a scalar?
A quantity with magnitude only
Examples of vectors
Displacement, velocity, acceleration, force, weight, momentum
Examples of scalers
Distance, mass, speed, energy
What is the difference between speed and velocity?
Speed is scalar so it only has a magnitude but velocity is a vector so it has direction and magnitude
What is the equation for speed?
Speed (m/s) = distance (m) / time (s)
What is the equation for acceleration?
Acceleration (m/s2) = change in velocity (m/s) / time taken (s)
a = (v - u)
/t
V= final velocity
U= initial velocityWhat is acceleration?
The change in velocity in a certain amount of time
How do you find the speed on a curved distance time graph?
Draw a tangent to find the gradient. Use equation if finding distance.
How do you find the distance travelled on a velocity time graph?
Find the area under the graph
What is the value of acceleration due to gravity?
10 m/s2
What is momentum?
The product of the objects mass and velocity
What is the equation for momentum?
Momentum (kg m/s) = mass (kg) x velocity (m/s)
P= m x v
What is Newton’s second law equation for force?
Force (N) = mass (kg) x acceleration (m/s2)
What is the thinking distance?
The distance the car travels in the drivers reaction time
What is thinking distance affected by?
Increased by tiredness, alcohol, drugs and distractions
What is braking distance?
The distance taken to stop once the brakes have been applied
What is braking distance affected by?
Speed of car, mass of car, friction between tyres and road, road conditions eg icy wet, or if tyres are worn
Explain how human reaction time is measured using computer based test
Clicking and mouse when the screen changes colour and timing reaction time
Explain how human reaction time can be measured using ruler drop test
One person holds top of ruler one person touches bottom. Top person drops it and the measurement is how far ruler dropped in time to react.
What is the typical reaction time for ruler drop test
0.2s - 0.6s
How do you find the stopping distance of a vehicle?
Thinking distance + braking distance
