Vocab
Change is position is also known as this.
Displacement
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
If 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?
They 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 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?
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 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 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
The path followed by a projectile
Trajectory
A jet accelerates for 2 minutes at a rate of 0.2 m/s2 its final speed is 84 m/s. What was its displacement during this time?
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
You walk on a moving walkway that is 85 m long and has a speed of 2.2 m/s relative to the ground. If it takes you 68s to cover 85m when walking on the ground, how long will it take you to cover the same distance on the walkway? Assume that you walk with the same speed on the walkway as you do on the ground.
25 s