Units
What is the correct unit for speed?
a)m/s - metres per second
What is the difference between speed and velocity?
Velocity also has a direction, speed does not.
To calculate momentum, which pieces of information do you need?
The mass of the object and its velocity.
What does acceleration describe?
a change in velocity
What goes in the x-axis of the graphs seen in class?
time (s)
What is the SI unit for time?
seconds or hours
Write down the equation to calculate speed.
s=d/t
A 2 kg ball is moving at a velocity of 5 m/s towards the goal. What is the momentum of the ball?
10 kg·m/s towards the goal
To calculate acceleration, which pieces of information do you need?
The time taken to change velocity.
What does a horizontal (flat) line on a distance-time graph indicate?
a)The object is not moving.
What is the SI unit for distance?
m or km
A car travels 150 kilometers in 3 hours. What is the average speed of the car?
50 km/h
A 650g ball is moving at a velocity of 12 m/s towards the goal. What is the momentum of the ball?
7.8 kg·m/s
If you were given a negative value for acceleration, what could this mean?
The object is slowing down.
On a velocity-time graph, what does a horizontal (flat) line show?
The object is moving with a constant speed.
What is the correct unit for acceleration?
m/s2
Jane runs a 100 meter race in 8 seconds. What was her average speed?
12.5 m/s
A soccer ball is at rest and is kicked with a force that causes it to move at 12 m/s to the right. The momentum is 18 kg•m/s. What was the mass of the soccer ball?
1.5 kg
Explain why an object moving in a circle is accelerating, even if it moves with a constant speed.
changing direction
PAPER AND PENCIL: Sketch a distance-time graph for a journey along the motorway where the driver stopped once for petrol.
l /
l _______/
l /
l /
_/_________________________
time
What is the correct unit for momentum?
kg•m/s
How long does it take a car traveling at an average speed of 20 m/s to complete a 4 km journey?
200s
Two objects, a 3 kg ball and a 6 kg ball, are moving towards each other. The 3 kg ball has a velocity of 4 m/s, and the 6 kg ball has a velocity of 2 m/s. What is the total momentum of the system before the collision if they move towards each other?
0 kg·m/s
A plane is traveling at 80 m/s. To prepare for landing, it decreases its speed to 50 m/s in 120 s.
-0.25 m/s2
Explain how the area under a velocity-time graph may be found, and its use.
finding distance