Forces
Newton's Laws
Pressure
Floating and Sinking
Grab Bag
100
Which is greater, rolling friction or sliding friction?
Sliding friction
100
The tendency of an object to resist a change in motion is called __________.
Inertia
100
What is the unit for pressure?
Pascal (Pa)
100
In water, an object with a density of 0.50g/cm3 will _______.
Float
100
Momentum is equal to...
Mass x Velocity Bonus: What are the units of momentum?
200
Forces can be added together only when they are acting on the _____________ object.
same Bonus (100pt): If there is no change in motion, the net force must be _____.
200
A 5kg ball is accelerated 25m/s2 by a force of _______.
F=MA F=5kg(25m/s2)=125N Bonus (50pts): If the mass increases, the force will ___________.
200
A pascal is equal to
1N/M2
200
What is the formula for density?
Density = Mass/Volume
200
Why does a hot air balloon rise?
Because hot air is less dense than cold air.
300
A snowboarder rides south with a force of 15N. The snow exerts a friction force of 3N. What is the net force?
12N South Bonus (100pts): What kind of friction is this?
300
What is the reaction force that causes a rocket to launch?
The force of the air pushing back on the rocket. (Upward)
300
How do fluids exert pressure?
In all directions.
300
Why are you not crushed by air or water pressure?
Fluids inside your body exert an outward pressure. (And the pressure is from all directions)
300
According to Archimedes Principle, a person that displaces an amount of water that weighs 10N, will experience a buoyant force of _______.
10N
400
A Newton is equal to __________. (units)
kg m/s2 (Think: F=MA)
400
The amount of matter in an object is the _________.
Mass
400
How does water pressure change with depth?
Increases
400
The amount of water an object displaces is equal to its
Volume
400
What direction does the buoyant force act?
Upward Bonus (100pt): What causes the buoyant force?
500
The universal law of gravitation says that when mass increases, gravity ______________.
Increases Bonus (50pts): When distances increases, gravity ___________.
500
What is the acceleration of a 15kg object moved with 8N of force?
F=MA A=F/M=8N/15kg=.53 m/s2
500
A man exerts a force of 10N over an area of 2m2 while snowshoeing. What is the pressure?
Pressure= Force/Area=10N/2m2= 5Pa Bonus (100pts): What is the pressure if the man stands on one foot?
500
An object has a mass of 50g and a volume of 5cm3. What is its density?
Density=Mass/Volume=50g/5cm3=10g/cm3 Bonus: What would the density be if the volume were double?
500
A 50kg car is moving 50m/s when it collides with truck that weighs 75kg and is moving 10m/s. What is the total momentum?
p=MxV=(50kgx50m/s) + (75kg x 10m/s) =2500kgm/s + 750kgm/s = 3250kgm/s
M
e
n
u