Units
What are the units of speed?
m/s
What is speed?
How fast an object is moving
The _______ force is the sum of all forces
Net
A car is travelling at a speed of 50 km/h. What is the distance covered by the car in 30 minutes?
Distance = speed x time
Convert time to hours 30 minute = 0.5 hours
Distance = 50 x 0.5 = 25 km
What are the units of force?
Newtons (N)
What is velocity?
How fast and object is moving in a given direction.
Speed and direction of an object
The 3 kinds of friction are _________, __________ & ______________
Static, sliding and rolling friction
As you get further away from the earth, your weight would:
A) Increase
B) Decrease
C) Stay the same
B) Decrease
A 2 kg ball is on the top of a building that is 12 m high. How much gravitational potential energy does the ball have?
GPE = 2 x 9.8 x 12
GPE = 235.2 J
What is the unit of work?
Joule (J)
What is distance?
How far an object has travelled
When an object experiences two forces that are equal in size and opposite in direction, the object is in ____________
Equilibrium
The slope of the velocity-time graph is called the _________
Acceleration
A 5 kg ball has a kinetic energy of 40 J. How fast is it going?
KE = 1/2 m v2
40 = 1/2 x 5 x v2
80 = 5 x v2
v2 = 16
v = 4 m/s
What are the units of momentum?
kg m/s
What is displacement?
The difference between an object's starting and finishing point
Velocity is the rate of change of _____________
Position
Distance is ___________ displacement
I. Equal to
II. Greater than
III. Less than
Pick however many options you see fit
Greater than or equal to
A 500 kg car is going at 60 m/s to the right and comes to a stop in 10s. What is the breaking force that was applied to the car?
(Double points for a perfect answer)
F = ma
a = vf - vi/t = 0 - 60 / 10 = - 6 m/s2
F = 500 x - 6 = - 3000 N right or 3000 N left
What is the unit of gravitational strength?
N/ kg or m/s2
What is gravity?
An attractive force between any two objects with mass
Acceleration is the rate of change of ___________
When is distance equal to displacement?
If a body is moving in a straight line
DOUBLE POINTS
Calculate the gravitational force between the earth and the sun. The mass of the earth is 5.972 × 1024 kg and the mass of the sun is 1.989 × 1030 kg.
The distance between the earth and sun is 1.5 × 1011 m
Fg = Gm1m2/d2
Fg = (6.67 x 10-11)(5.972 x 1024)(1.989 x 1030)/ (1.5 x 1011) = 5.28 x 1033 N