Vocab
Change is position is also known as this.
Displacement
A car in front of the school goes from rest to 22 m/s in 4.0 seconds. Identify the three known variables
Vi=0 Vf=22 t=4
A car in front of the school goes from rest to 30 m/s in 6.0 seconds. What is its acceleration?
-5 m/s2
Motion in the x-direction and motion in the y-direction are ______.
Independent
3.2 s
A bullet starting from rest accelerates at 4000 m/s2 down a 0.1 m long barrel. Identify the known variables
vi= 0 a= 4000 x=0.1
f a car’s brakes can decelerate the car at a rate of 3.0 m/s2, what is the minimum stopping distance of a car that is initially traveling 40.0 m/s?
16.3 m
A ball rolls at a velocity of 6 m/s at an angle 40 degrees North of East. What is the x-velocity and y-velocity of the object
vx= 4.6 m/s
vy= 3.9 m/s
Two balls are thrown from a height of 10 m. The blue ball is thrown at a horizontal speed of 10 m/s while the red ball is thrown at a horizontal speed of 20 m/s. If both balls are thrown at the same time, which reaches the ground first?
The hit at the same time!
An object in free fall, generally moving forward as well as downward, is known as what?
A projectile
An airplane touches down at a speed of 60.0 m/s on a runway that is 800 m long. The plane can decelerate at a uniform rate of 2.75 m/s2. Can the plane come to a stop along the runway?
vi= 60 a=-2.75 vf= 0
An airplane touches down at a speed of 40.0 m/s on a runway that is 800. m long. The plane can decelerate at a uniform rate of 1.75 m/s2. Will the plane be able to stop before the end of the runway? (you must show work to get your points)
yes
A hiker goes 5 miles North, 2 miles West, 1 mile north, the 4 miles east.
What was the hikers total displacement, magnitude and direction?
6.3 m 72 degrees N of E or 18 E of N
A cannon is on top of a 100 meter tall hill and launches a cannon ball with a horizontal speed of 8 m/s. What is the range of the cannon ball?
t= 4.5 s
x= 36.1 m
You can use this branch of physics to predict how an object will behave based on a few initial conditions
Kinematics
A snow ball is thrown upward at a speed of 30 m/s. When does the snow ball reach its' peak? Identify the unknown variables (Hint: There are only 2)
Displacement and Time
A bullet starting from rest accelerates at 4000 m/s2 down a 0.2 m long barrel.
What is the velocity of the bullet as it leaves the barrel of the gun?
How long does it take the bullet to leave the barrel?
vf= 40 m/s
t=0.01 s
A boat is traveling across a 50 m wide river with a speed of 4 m/s directed towards the other side. The river has a current of 5 m/s. How long does it take the boat to cross the river? How far down river does the boat travel?
t=12.5 s
x= 62.5 m
A fire fighter helicopter drops a load of water while flying. The pliot is flying the helicopter forward at 45 m/s and knows to drop the water 250 meters ahead of the fire. How high up is the helicopter?
151.2 mhigh
The path followed by a projectile
Trajectory
A cannon is on top of a 50 m tall wall and shots a cannonball horizontally at a speed of 10 m/s.
y=50 vyi=0 a=9.8
vx=10
A jet accelerates for 2 minutes at a rate of 0.2 m/s2 its final speed is 84 m/s. What was his displacement during this time? (vi is not zero)
8,640 m
A ball rolls along the ground at an angle 30° S of E at a speed of 12 m/s.
(a) What is the x-velocity? (b) What is the y-velocity? (b) How long does it take the ball to travel 60 m South? (d) How far south does the ball travel in this time?
(a) vx=10.4 m/s east
(b) vy= 6 m/s south
(c) 10 s
(d) 104 m south
A football player kicks a football at a speed of 32 m/s at an angle of 25 degrees above the horizontal. What is the range of the football?
80 m