1Define scalar quantity
A measurement that does not contain directional information, just size
2Define vector quantity
a measurement that has both magnitude and direction
3What's the difference between scalar and vector quantities?
Vector contains direction as well as size whereas scalar is just size
4Is displacement scalar or vector?
vector
5Is distance scalar or vector?
scalar
6Is velocity scalar or vector?
vector
7Is speed scalar or vector?
scalar
8Is acceleration scalar or vector?
vector
9Is force a scalar or a vector?
vector
10Is weight scalar or vector?
vector
11Is mass scalar or vector?
scalar
12Is momentum a vector or a scalar?
vector
13Is energy scalar or vector?
scalar
14What is velocity?
speed with a direction
15What's the equation for speed?
speed(m/s) = distance(m)/time(s)
16What is the equation for distance?
distance(m) = average speed(m/s) x time(s)
17How to find the speed from distance/time graphs
It's the gradient
18What's the equation for acceleration?
Acceleration(m/s2) = change in velocity(m/s) / time taken(s)
19How to calculate the acceleration in velocity/time graphs
acceleration is the gradient
20How to find the distance travelled in velocity/time graphs
It's the area between the graph line and the time axis
21Define centripetal force
A force that causes an object to move in a circle. Since in a circle, the direction always changes, so does the velocity resulting in acceleration
22Where does centripetal force act on?
Towards the centre of the circle
23Describe a method to measure speed
1. Measure a fixed distance with a ruler (over 400m for sound)
2.Time with a stop watch how long it takes to cover that distance
3. Use speed=distance/time
24Describe how to measure speed with light gates
1.Set up light gates and measure the distance between them using a ruler
2. Push through the first light gate, the second will stop the time
3. Use speed= distance/time
25What is the typical walking speed?
1.5 m/s
26What is typical running speed?
3 m/s
27What is typical cycling speed?
6 m/s
28What is typical car speed?
10-30 m/s
29What is typical plane speed?
250 m/s
30What is typical speed of sound?
330-400 m/s
31What is typical speed of wind?
6 m/s
32What is the acceleration due to gravity?
10 m/s2
33What is Newton's first law?
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
34What happens when the resultant force on a body is 0?
A stationary object stays stationary
A moving object continues to move at the same velocity
35What happens when the resultant force is not 0?
A stationary object will start moving
A moving object will change speed or direction
36What's Newton's second law?
Force (N)= mass (kg)x acceleration(m/s2)
F=ma
37Define weight
the force of gravity on an object
38What's the equation for weight?
Weight(n)= mass (kg)x gravitational field strength(N/kg)
39Describe internal mass
The ratio of force over acceleration. How hard it is to change the velocity
40Describe how weight measured
You have to measure the force pulling the object towards the centre of the Earth
41What is Newton's third law?
For every action there is an equal and opposite reaction
42Give an example of Newton's third law
If you push down on your chair, your chair pushes back up on you
43Define momentum
The product of an object's mass and velocity
44What's the equation for momentum?
momentum( kg m/s) = mass(kg) x velocity(m/s)
45What is equilibrium?
a state in which opposing forces or influences are balanced.
46What happens to objects in collision interactions?
They may have different effects due to different masses
47What is the conservation of momentum?
In a closed system, the total momentum before an event is the same as after the event
48Describe examples of momentum in collisions
When a canon is fired, the cannon ball gains a forward momentum and the canon gains a backward momentum
49What's the equation for force with momentum?
Force(N)= change in momentum(kg m/s)/time(s)
50How to measure human reaction times
drop ruler
51What's a human's typical reaction time?
0.2-0.9s
52What is stopping distance?
Thinking distance + braking distance
53What is stopping distance of a vehicle effected by?
mass of vehicle, speed of vehicle, driver's reaction time, state of the vehicle's brakes, state of the road, amount of friction
54What can affect a driver's reaction time?
Tiredness, drugs, alcohol, distractions
55What are the dangers caused by large decelerations?
The brakes can overheat and the driver can lose control
56How to estimate the forces involved in a typical situation on a public road
1. Use Acceleration= change in velocity/time to find the accelerate , knowing average speed of a car is 20 m/s
2. Use force= mass x acceleration to find the force