Forces & Motion Review

Vocabulary

100

the tendency of an object to resist a change in its motion

inertia

200

two equal forces acting in opposite directions on an object

balanced force

300

The state of an object when it is not in motion

at rest

400

Distance and direction of an object's change in position from the starting point.

displacement

500

a physical quantity that has magnitude but no direction.

scalar

Laws of Physics

100

the total energy of an isolated system remains constant over time, meaning energy cannot be created or destroyed, only transferred or transformed from one form to another

Law of Conservation of Energy

200

the state of motion of an object does not change as long as the net force acting on the object is zero

Newton's 1st Law (AKA the Law of Inertia)

300

whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object.

Newton's 3rd Law of Motion

400

states that the amount of momentum remains constant and is neither created nor destroyed, but only changed through the action of forces

Law of Conservation of Momentum

500

the acceleration of an object is equal to the net force acting on it divided by the object's mass

Newton's 2nd Law of Motion

Forces

100

center directed force that constantly changes an object's direction of motion

centripetal force

200

two or more forces that are not equal and opposite of one another; can cause change in motion

unbalanced force

300

associated with charged particles; like charges repel and opposite attract

electromagnetic forces

400

holds protons and neutrons together in the nucleus

strong nuclear force

500

List 2 ways to increase the strength of gravitational force.

1) decrease distance

2) increase mass

Formulas

100

__ = displacement / time

velocity (v)

DD: what is the SI unit for velocity?

200

F_g = m x ____

acceleration due to gravity (g)

DD: What is g on the Earth?

300

____ = (v_f - v_i) / t

acceleration (a)

DD: What is the SI unit for acceleration?

400

P = ___ / t

Work (W)

DD: How do you find work? In other words, what is the formula for work?

500

p = ?

momentum (p) = mass (m) x velocity (v)

DD: which would have more momentum? A car going 20 mph or a skateboarder going 20 mph?

Calculations

100

An 3 kg apple is thrown at 10 m/s. What is its momentum?

p = 30 kg*m/s

200

A drag racecar at rest speeds up to 45 m/s in 5 seconds. What is the car's acceleration?

a = 9 m/s²

300

What is the weight of an egg if it has a mass of 0.05 kg?

F_g = 0.49 N

400

How much work is applied to your backpack if 11 W of power is used for 681 seconds?

W = 7,491 J

500

How much work is required to lift a 20 kg sack of potatoes 6.5 m high?

W = 1,274 J