Patterns of Motion
Which is more fundamental, mass or weight?
Mass
What equation is stated by Newton's 2nd Law?
F=MA (Force=mass x acceleration)
Can energy be created or destroyed?
No
A 50kg skater pushed by a friend accelerates 5 m/s^2. How much force did the friend apply?
F= 250 N
Newton's 3rd Law
What is the acceleration of gravity?
9.8 m/s^2
Describe the concept of inertia
Every object continues in a state of rest or state of motion unless it is compelled to change that state by another force.
What is the difference between potential and kinetic energy?
Potential energy is stored energy, kinetic energy is energy in motion.
You drop a 40 N box out of a window 50 m above the ground. What is its kinetic energy when it hits the ground?
2000 Joules
Define hypothesis
An educated guess
What is the difference between speed and velocity?
Velocity includes the direction of motion
Describe Newton's 3rd Law
When an object exerts a force on a second object, the second object exerts an equal and opposite force on the first. (Action-Reaction)
What is the unit we use for energy and work?
Joule (J)
A 6 kg fish swimming at 3 m/s eats a 3 kg fish. What is his speed now?
2 m/s
If the sum of all forces on an object is zero, what is the acceleration of the object?
Zero
How many Newtons is 1 kg?
9.8 N
What is terminal speed?
speed at which acceleration of a falling object terminates when air resistance balances its weight.
If you exert the same amount of work in half the time, what happens to your power output?
(Hint: P=w/t)
It doubles.
You are pushing a cart to the left with a force of 150 N. Your sister is pushing the cart to the right with a force of 210 N. Your brother joins you in pushing the cart to the left, and he is pushing with a force of 130 N. What is the net force on the cart?
70 N
A 3000 N bear grasping a vertical tree slides down at constant velocity. The friction force between the tree and the bear is:
3000 N
List the units for mass, weight, speed, velocity, and acceleration
Mass: Kilogram
Weight: Newton
Speed: m/s
Velocity: m/s
Acceleration: m/s^2
How do you find net force? (Can use word problem example to explain)
Add force vectors to find net force.
What is the work energy theorem? (Can describe or give equation)
Work equals change in kinetic energy
Fd= (1/2 mv2)after-(1/2 mv2)before
Pt. 1: A 2010 Ford Mustang can accelerate from 0 to 26.8 m/s in 4.9 seconds. What is the acceleration of the car?
Pt. 2: If acceleration is constant, how far will the car travel in that period of time?
5.5 m/s^2
66m
A man weighing 800N stands with his weight equally distributed onto 2 scales. What does each scale read?
400N