What happens when 2 forces act in the same direction?
The magnitude of the forces is added together.
100
What do we call the tendency of an object to resist change in motion?
Inertia
100
True or False? Buoyancy acts in a downward direction.
False
100
What is the force that causes an object to move in a circle?
Centripetal Force
200
If you know both the SPEED and DIRECTION of an object, then you know the _______ of the object.
VELOCITY
200
The greater the mass of an object, the _________ its inertia.
GREATER
200
What is the formula to calculate FORCE?
Force=Mass x Acceleration
200
How is the density of a submarine decreased?
It releases water from its floatation tanks.
200
Give an example of intentionally decreasing friction.
Answers will vary. Some examples include:
-waxing skis
-adding grease to gears on a bike
-oiling a squeaky door
300
What do we call the rate at which velocity changes?
Acceleration
300
Forces can be added together only if they are what?
acting on the same object or acting in the same direction.
300
According to Newton's 3rd Law, what happens to the nail when a hammer strikes and exerts a force on a nail?
The nail exerts an equal force back on the hammer.
300
Explain why it is easier to float in the ocean than it is to float in Lake Michigan. Include the word "dense" or "density" in your answer.
The ocean's water is more dense because of the salt mixed in with the water. Since the water is more dense, objects become more buoyant.
300
Explain why you would weigh less on the moon.
The moon is 1/6 the size of the Earth, so there is only 1/6 the gravity on the moon as on Earth.
400
What is the average speed of a train that is travels 100 kilometers in 4 hours? (Don't forget to include UNITS in your answer!)
25 km/hr
400
State Newton's Second Law.
Then, give an example.
Force = Mass x Acceleration
Examples will vary.
400
State Newton's 1st Law.
Then, give an example.
An object at rest will remain at rest, and an object in motion will remain in motion, unless acted on by an outside force. Also known as the law of INERTIA.
Examples will vary.
400
Explain why your ball of clay sank and your clay boat floated.
Although the pieces of clay were the same mass, the density of the boat was less, since we increased the volume and filled the empty space with air.
Density = Mass / Volume
400
Explain why your mass is the same on Earth as it is on the moon.
Mass is a measure of the amount of matter in an object. This number is not dependent on location.
500
What is the formula for calculating density?
Density = Mass / Volume
500
What happens when 2 opposing forces are acting on an object?
The resulting force is the DIFFERENCE between the 2 forces.
500
A rocket lifting off the ground and into space can be explained by which of Newton's Laws?
Newton's Third Law- For every action, there is an equal and opposite reaction.
500
Explain why a ship stays afloat.
The buoyant force is greater than the ships weight.
500
What do we call the force of gravity on a person or object at the surface of a planet?