Force
Different between lift and thrust.
lift = an upward force on an object that moves in a fluid.
thrust = the pushing or pulling force exerted by the engine of an aircraft or rocket.
objects don't travel at a constant speed so we calculate things by taking their?
average speed = total distance/total time
What's the maximum speed a falling object can reach called?
terminal velocity
the higher you go in the atmosphere, what happens to the pressure?
pressure drops and becomes nonexistent
If I push my desk with a force of 30 N and Gia pulls with a force of 25 N on opposite directions, what is the net force?
55 N
the mount of friction depends on the what?
amount of force pushing the surfaces together.
North, south, and right are what we call?
reference direction
What year did Isaac Newton start to create the idea of gravity?
1665
air is _____ ______ dense than water. *two worded answer*
1000 less
What is the pressure exerted by a book that has an area of 0.3 m^2 and a weight of 12 N?
40 N/m^2
What do I call the bumps and divots on surfaces that relate to friction?
hills and valleys
the curved path that an object follows when thrown, launched, or otherwise projected near the surface of Earth.
projectile motion
Gravitational force decreases as ________ increases.
distance
When someone is in water what two things are pushing on the diver?
atmospheric and water pressure
Find the density of a rock that has a mass of 18 g and a volume of 3 cm^3?
6 g/cm^3
Name two ways to reduce and two ways to increase friction.
increase = increase surface area, make something rougher, add texture, increase force pushing on the surfaces
decrease = lubricant, smooth rough surfaces, reduce force pushing on the surfaces, going from sliding to rolling kinetic
What is Newton's first law of motion?
an object remains at rest or moves at a constant speed in a straight line unless acted upon an unbalanced force.
What do you need to have free fall?
to have only the force of gravity acting on a body.
What causes a tornado?
high air pressure on the outside rushing into the center towards low pressure creating a vacuum effect.
A stone at rest is dropped from a cliff and the stone hits the ground after a time of 3 seconds. What's the stone's velocity when it hits the ground?
29.4 m/s
When the forces on an object produce a net force of 0 N, the forces are _____?
balanced
What's the difference between acceleration, velocity, and speed?
speed = distance over time
velocity = speed in a direction
acceleration = rate at which velocity changes
The law of universal gravitation claims two things. What are they?
1. all objects attract each other through gravitational force.
2. the size of the force depends on the masses of the objects .
What does pressure have to do with breathing?
when you breath in, it expands your lungs which lowers the pressure. Your lungs are now a lower pressure than the surrounding air so air rushes in to balance.
What is the weight of a box who has a base which is 4 square inches and exerts a pressure of 13.5 pounds per square inch?
54 lbs