Forces and Motion Flashcards
(25 cards)
Explain what is meant by a scalar quantity.
Give 2 examples
A scalar quantity is a magnitude. It can be described fully with a single numerical value
Ex:distance, speed, time, mass, energy..
Explain what is meant by a vector quantity.
Give 2 examples
A vector quantity has both a magnitude and a direction.
Ex: Force, velocity, displacement, momentum, moment…
Which property of a distance-time graph can be used to calculate speed?
Gradient (or Slope)
For the d-t graphs given below, decide which one is at rest, which one is moving with constant speed and which one is accelerating
State an equation linking distance moved, time taken and average speed with their respective units.
Average speed(m/s) = Distance(m) / Time(s)
v=d/t
What is meant by acceleration? Give its unit.
Acceleration is the change in velocity per unit of time.
State an equation linking acceleration, change in velocity and time taken
Acceleration =(Change in velocity)/ time
a = (v-u) / t
v: final velocity u: initial velocity
Which property of a velocity-time graph can be used to calculate acceleration?
Gradient (slope)
Which property of a velocity-time graph can be used to calculate distance travelled?
Area under the graph
For the v-t graphs given below, decide which one is accelerating; moving with constant speed or decelerating
State an equation linking final speed, initial speed, acceleration and distance travelled
Identify the types of forces acting on the objects
Name two types of forces that always opposes motion
- Friction
- Air Resistance (Drag)
a) Which type of force holds planets around the Sun?
b) Which type of force holds electrons around nucleus?
A) Gravitational Force
B) Electrostatic Force
State the ways that a force can affect the body that it is being applied on.
-It can change the shape of the object (extension/compression)
-It can change the speed of the object
-It can change the direction the object is moving
Calculate the resultant force for the objects below and state the direction
What magnitude would the resultant force have and in what direction would it be pointing?
State an equation linking unbalanced force, mass and acceleration
State an equation linking mass, weight and gravitational acceleration
What is the relationship between stopping distance, braking distance and thinking distance of a car while stopping?
Stopping Dist. = Thinking Dist. + Braking Dist.
State 4 factors that affect the stopping distance of a car
- Reaction time
- Weather conditions
- Initial speed
- Driver’s conditions
- Road Conditions
- Mass of the car
- Tire Conditions
State two factors that affect the air resistance acting on a falling object
- Surface Area
- Speed
Describe how a falling object reaches to terminal velocity.
At first object falls under the effect of its weight accelerating with g. As it accelerates, air resistance opposing the motion increases therefore resultant force acting on the object decreases and since F=ma, acceleration decreases. When air resistance becomes equal to weight, forces are balanced so resultant force=0 therefore a=0 and object reaches to terminal velocity.
State what is meant by obeying Hooke’s Law
Extension is directly proportional with the force applied.
