Kinematics
Projectile Motion
Equations
Physicists
100

It takes you 9.5 minutes to walk with an average velocity of 1.2 m/s to the north from the bus stop to museum entrance. What is your displacement?


Answer=5415m

If you travel along the straight line than the displacement is equal to the traveled distance.

s=vt

where v=1.2 m/s and t= 9.5 minutes

9.5(60s)=570s

s=9.5(570)=5415m

100
What is the acceleration due to gravity?
9.8 m/s^2
100
F= ?

F=ma

Extra 100 points: F= change in p over change in t

change in momentum, Δp, with the corresponding change in time, Δt

100
What is Newton's third law?
Forces exist in pairs, when 2 bodies interact, the forces they exert on each other are equal in magnitude and opposite in direction.
200

An airliner reaches its takeoff speed of 163 mph in 36.2 s. What is the magnitude of its average acceleration.


Answer: What is 2 m/s^2

163 mph = 0.447*163 m/s = 72.9 m/s. The traveled time is 36.2 s.

Then the average acceleration is

a=72.9/36.2

=2 m/s^2

200

 An object is launched at a velocity of 20 m/s in a direction making an angle of 25° upward with the horizontal. 

Answer= 3.64 meters

maximum height y (0.86) = 20 sin(25°)(0.86) - (1/2) (9.8) (0.86) 2 = 3.64 meters


200
Momentum = ?

Δp=F(Δt)

200
What is Kirchoff's first law?

Current flowing into a node (or a junction) must be equal to current flowing out of it

300

A rock is thrown straight upward off the edge of a balcony that is 5 m above the ground. The rock rises 10 m, then falls all the way down to the ground below the balcony. What is the rock's displacement?

Displacement deals only with the initial and final positions of the rock. The rock's initial position is the balcony, and its final position is the ground 5 m below. So, the rock's displacement is 5 m downward.

300

A ball is kicked at an angle of 35° with the ground. What is the time for the ball to reach the target? 

t = x / V cos(35°) = 2.0 s

300
Acceleration=?

a=Δv/Δt

300
What is Newton's second law?
For a body of constant mass, the acceleration is directly proportional to the resultant force applied to it. Resultant force, F, mass, m, and acceleration, a, are related by the equation F=ma
400

An athlete runs exactly once around a circular track with a total length of 500 m. Find the runner's displacement for the race.

Since the athlete runs exactly once around the circular track, that means that he/she finishes at the same point where he/she started, meaning the initial and final positions are the same. 

400
Projectile motion = accelerated motion in __ direction and constant velocity in __ direction

Options: x or y

accelerated motion in y direction and constant velocity in x direction
400
Work=?
Work=Force(Displacement)


400
What is Newton's first law?
An object will remain at rest or in a state of uniform motion unless it is acted on by an external force.
500

A car drives in a straight line at a constant speed of 60 miles per hour for 5 seconds. Find its acceleration.


Since the car's velocity is constant, there is no acceleration. So, a = 0.


500
What are the four big equations?
v=u+at

v^2=u^2+2as

s=1/2(u+v)t

s=ut+1/2at^2

500
Velocity is the rate of change of ?
Displacement
500
What is Kirchoff's second law?

The net electromotive force around a closed circuit loop is equal to the sum of potential drops around the loop

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