P2.1 Flashcards
Displacement
A measure of how far an object moves in a given direction it is the straight line between the starting and finishing points and is a vector quantity
E.g 10m north
Displacement = initial velocity * time + 1/2* acceleration*time^2
Displacement = velocity * time
Distance
A measure of how far an object moves. It doesn’t depend on direction, and is therefore a scalar quantity.
Distance = speed * time
Velocity
Speed
Vector quantity
One that depends on magnitude and direction e.g velocity and acceleration
Scalar quantity
One that only takes magnitude into account e.g distance
Acceleration
Rate of change of velocity
Can be cal from gradient of velocity-time graph
Acceleration = change in velocity / time
A cat skulks 20m in 50s find
A) speed
B) how long it takes to skulk 32m
A) 0.4m/s
B) 80s
Cyclist has constant speed. Calculate their speed if they cycle 660m in 2 minutes
5.5m/s
Distance travelled in 24s by a car with constant speed of 54 km/hr
360m
Uniform acceleration
Final velocity^2 - initial velocity^2 = 2(acceleration * distance)
A horse is running with constant acceleration of 0.45 m/s^2. It has an initial velocity of 8m/s and runs a distance of 180m. What is final velocity to 2s.f
15m/s
A cheetah with an acceleration of 8.25 m/s^2 takes 4.0 seconds to reach its maximum speed from rest. Calculate its maximum speed and the distance covered in this time. (4 marks)
Change in velocity = acceleration * time
=8.25 * 4
= 33m/s
V^2 - u^2 = 2ad
D= (v^2 - u^2) / (2a)
= 33^2 - 0^2 / 2*8.25
= 66m
Gradient of D-T graph
Speed of object
Curve on D-T graph
Acceleration
Steeper D-T graph
Fast
