Formulas
What is the formula for velocity?
V=d/t
What does the slope of a p-t graph represent?
Velocity
Define velocity in regards to position and time
As position increases, time increases and velocity of the object will increase as well.
A man runs 7 km in 2 hours and 2 km in 1 hour in the same direction.
a) What is the man's average speed for the whole journey? (do not adjust for m/s)
3 km/h
What is the kinematic equation for final velocity when given displacement?
Vf^2=Vo^2+2a(delta X)
What is the formula for acceleration?
A=v/t
What does the slope of a V-t graph represent?
Acceleration
Define acceleration in regards to velocity and time
As velocity increases and time increases, acceleration increases as well
A man walks 7 km East in 2 hours and then 2.5 km West in 1 hour.
b) What is the man's average velocity for the whole journey?
3.2 km/hr
What is the kinematic formula for final velocity given time?
Vf=Vo+a(t)
What is the formula for displacement?
Xf-Xi
What does a P-t graph look like when an object is slowing down?
A curved slope going down towards the X axis
How does mass affect the motion of an object in free fall?
It does not
John drove South 120 km at 60 km/h and then East 150 km at 50 km/h.
a) the average speed for the whole journey?
The time t1 to cover 120 km at a speed of 60 km/h is given by
t1 = 120 / 60 = 2 hours
The time t2 to cover 150 km at a speed of 50 km/h is given by
t2 = 150 / 50 = 3 hours
average speed = distance/time
=120 km + 150 km
2 hours + 3 hours
=270 km/5 hours
AVG = 54 km/h
An object is dropped from rest from the top of a tall bulding. It hits the ground 5 seconds after it is dropped. What is the height of the building?
x=125 m
How do you calculate total distance?
Add all distances (regardless of direction)
What does a P-t graph look like when an object is speeding up?
A curved slope going up and away from the X-axis
What is a scalar quantity?
A vector that is described only by magnitude
A car accelerates from rest to a speed of 36 km/h in 20 seconds. What is the acceleration of the car in m/s2?
The initial velocity is 0 (from rest) and the final velocity is 36 km/h. Hence
average acceleration = ( 36 km/h - 0 ) / 20 seconds = 36 km/h / 20 secondsWe now convert 36 km/h into m/s as follows
36 km/h = 36 * 1000 m / 3600 s = 10 m/s
average acceleration = 10 m/s / 20 seconds = 0.5 m/s 2
Upton chuck is riding the giant drop at great America. If upton free falls for 2.6 seconds what is his final velocity?
Vf= 26 m/s
What is the kinematic equation for displacement?
delta x=Vo(t)+1/2(a)(t)^2
They account for magnitude and direction
What is acceleration due to gravity when dealing with free fall?
10 m/s^2
A stone is released at rest from a height and falls freely for 4s. What is the height?
x=80m
Luke Autbeloe drops a pile of roof shingles from the top of a roof located 8.52 meters above the ground. Determine the time required for the shingles to reach the ground.
t=1.3 seconds