Motion (Speed, Velocity, Acceleration)
What is the difference between Speed and velocity?
Velocity is a vector quantity, while speed is a scalar quantity. Velocity can be zero, while speed cannot be zero.
What are Newtons laws of motion?
1st = An object in motion stays in motion, or an object at rest stays at rest until acted upon by an unbalanced force (law of inertia)
2nd = The force acting on an object is equal to the mass (in kg) times the acceleration of the object
F=ma
Force = mass x acceleration
3rd = For every action there is an equal and opposite reaction
What is force?
A push or pull one body exerts on another
What is work and what is power? How do you solve for them?
An object beings to move only when unbalanced forces act upon it. Work is done on an object when a force acts on the object in the direction the object moves.
W= Fd
Work= Force x Distance
Joules = Newtons x meters
The rate of doing work. Doing work at a faster rate requires more power
P = W/t
Power = Work/time
Watts = Joules/seconds
What is Energy?
The ability to do work (cause something to move)
What is the velocity of Maya running 400m if she starts at rest and it takes her 2 minutes?
200 m/s
What is interia?
Inertia is the tendency of an objects motion to resist change in motion (tendency to remain the same)
If Jiya is travelling at a final velocity of 25 m/s2, in a time of 45 seconds, and has a mass of 55kg, what is her force?
30.5 N
What is Watts?
A unit to describe power. It is measure of the rate of energy transfer over a unit of time.
How is energy related to work?
When work is done, you change the objects energy
What is Sydney's velocity if she runs 1 mile in 9 minutes.
1 mile = 1600m
1 min = 60 sec
2.96 m/s
Newtons 2nd law states the force acting on an object is equal to the mass (in kg) times the acceleration of the object. If Mias mass is 50kg, and her acceleration is 10 m/s2, what is her force?
500 N
What is the force of Mckenna if she has a mass of 45 kg if she accelerates at a rate of 5 m/s2
225 N
What is horsepower?
A unit of power. It is the rate at which work can be done. It was created to describe the amount of power an engine has. (It was used back in the day to compare steam engine power to how many horses could do an equal amount of power as the engine could do)
What are the 7 types of energy we have learned?
Chemical, nuclear, electrical, thermal, light, mechanical (gravitational energy and kinetic energy), sound
If Aubrey reaches a final velocity of 100 m/s2 while driving on the highway, and it takes her 40 seconds, what is her acceleration?
2.5 m/s2
Explain how 2 of Newtons laws of motion are applied when you drive a car.
1st law = The car moves when the force of your hand shifts the engine into gear.
2nd law = The force of the car on the road is equal to the cars mass times it's acceleration
3rd law = The car will remain still and wont move because the force of the car against the road is equal and in the opposite direction of the force of the road against the car.
What is the force of a 110 lb student who is accelerating at a rate of 5.5m/s2
1lb = 2.2 kg
110/2= 55
55 x 5.5 = 302.5
Force = 302.5 N
What is 25 horsepower in Watts?
25 x 746 = 18650 Watts
What factors influence kinetic energy?
Mass and speed
What is the difference between distance and displacement?
Distance is the total amount travelled between start and finish, no matter if it was a straight line or not, while displacement is the distance of a straight line between start and end.
What is a derived unit?
Two units combined together to make a unit
Ex: Newtons (unit for force)
Newtons = mass x acceleration
Why don't all objects appear to fall at the same rate on Earth?
The force of air resistance is heavier on some objects more than others. Air resistance is pushing an object in the opposite direction than the force of gravity is, which causes it to appear to be falling at a slower rate.
What is the power of a engine that is doing 3000 Joules in 15 seconds? (in horsepower)
1 horsepower = 746 Watts
0.2689 Horsepower
What factors influence gravitational (potential) energy?
Mass, gravity, height