Our Dynamic Universe Part 1 Flashcards
In the diagram shown, what force does the balance measure?
The balance will measure the reaction force (upwards).
What is meant by an ‘inelastic collision’?
An inelastic collision is one in which not all kinetic energy is conserved.
(i.e. some of the kinetic energy is lost)
Explain how you would resolve the vector shown into its horizontal and vertical components.
Use trigonometry (SOH CAH TOA):
Fhorizontal = F cos 𝜃
Fvertical = F sin 𝜃
What is impulse equivalent to?
Impulse is equivalent to change in momentum (of an object).
State the principle of conservation of momentum.
In the absence of external forces, the total momentum before a collision (or explosion) is equal to the total momentum after a collision.
You must include every part of this explanation!
Name the quantities shown in this formula.
W = weight
m = mass
g = gravitational field strength
What is the unit for impulse?
The unit for impulse is newton seconds (N s).
Explain how you would resolve the vector shown into its horizontal and vertical components.
Use trigonometry (SOH CAH TOA):
vh = v cos 𝜃 = 14 cos 20º
vv = v sin 𝜃 = 14 sin 20º
Explain the launch of a space rocket from Earth’s surface, in terms of Newton’s Laws.
According to Newton’s 2nd Law (F = ma) an unbalanced force will result in an object accelerating. A rocket has thrust (up) and weight (down) and if these forces are unbalanced, the rocket will accelerate.
What is meant by the term ‘impulse’?
Impulse is equal to force (on an object during a collision) multiplied by time (for the collision to take place).
In the diagram shown, the forces are balanced.
Describe the motion of the lift, and explain what the reading on the balance will be.
The lift will either be stationary or moving at constant speed.
The reading on the balance will be equal to the weight.
What is the unit for velocity?
The unit for velocity is metres per second (ms-1).
Name the quantities shown in this formula.
F = gravitational force
G = Universal Constant of Gravitation
m1 = mass
m2 = mass
r = distance between centre of masses
Describe the motion of the object whose displacement, velocity and acceleration is shown in these graphs:
This object has a negative acceleration (its speed is decreasing).
Describe the motion of the object whose displacement, velocity and acceleration is shown in these graphs:
This object is stationary.
Here is a displacement-time graph for an object.
What would the corresponding velocity-time graph look like?
Here is a displacement-time graph for an object.
What would the corresponding velocity-time graph look like?
What is the unit for energy?
The unit for energy is joules (J).
Describe the motion of the object whose displacement, velocity and acceleration is shown in these graphs:
This object is moving at steady / constant velocity.
Explain, in terms of forces, an object moving with terminal velocity.
The forces are balanced and the object moves at a steady speed.
The balanced forces are weight and air resistance.
Here is a velocity-time graph for an object.
What would the corresponding acceleration-time graph look like?
Here is a displacement-time graph for an object.
What would the corresponding velocity-time graph look like?
Describe the motion of the object whose displacement, velocity and acceleration is shown in these graphs:
This object has a positive acceleration (its velocity is increasing).
Name the quantities shown in these formulas.
u = initial velocity
v = final velocity
t = time
s = displacement
a = acceleration
Name the quantities shown in this formula.
F = force
m = mass
a = acceleration
In the graph shown, what quantity can be found by calculating the area under the graph?
The area under a F-t graph is equal to the impulse.
Here is a velocity-time graph for an object.
What would the corresponding acceleration-time graph look like?
Explain the motion of the skydiver, making reference to the forces acting.
The weight (down) is greater than the air resistance (up).
There is an unbalanced force acting on the skydiver.
The skydiver will accelerate (speed up).
What is the unit for displacement?
The unit for displacement is metres (m).
Name the quantities shown in this formula.
F = force
t = time
m = mass
v = final velocity
u = initial velocity
Name the quantities shown in this formula.
P = power
E = energy
t = time
What is the unit for force?
The unit for force is newtons (N).
What is the unit for acceleration?
The unit for acceleration is metres per second squared (ms-2).
Name the quantities shown in this formula.
p = momentum
m = mass
v = velocity
What is meant by an ‘elastic collision’?
An elastic collision is one in which all kinetic energy is conserved.
Here is a displacement-time graph for an object.
What would the corresponding velocity-time graph look like?
Here is a velocity-time graph for an object.
What would the corresponding acceleration-time graph look like?
What is the unit for gravitational field strength?
The unit for gravitational field strength is newtons per kilogram (Nkg-1) OR metres per second squared (ms-2).
Two identical objects are dropped.
One is dropped onto concrete. One is dropped onto a rubber mat.
On the graph shown, which line represents the concrete and which line represents the rubber mat?
A is concrete
B is rubber mat
Here is a velocity-time graph for an object.
What would the corresponding acceleration-time graph look like?
The diagram shows the forces acting on a mass on a slope.
How would the force parallel with the slope (Wparallel ) be calculated?
The magnitude of the force parallel with the slope = m g sin 𝜃
What is the unit for momentum?
The unit for momentum is kilograms metres per second (kgms-1).
What is the unit for mass?
The unit for mass is kilograms (kg).
What effect does friction have on a moving object?
Friction will:
- cause an object’s speed to decrease
- change some of the object’s potential or kinetic energy into heat energy
In the diagram shown, what is the value of the unbalanced force?
What is the value of the acceleration?
The unbalanced force is 40 - 10 = 30N.
The acceleration,
a = F/m = 1.5 ms-2.
Name the quantities shown in this formula.
Ew = work done
F = force
d = distance
Describe the motion of the skydiver, making reference to the forces acting.
The weight (down) is equal to the air resistance (up).
The forces acting on the skydiver are balanced.
The skydiver will move at a constant velocity.
(Although in Newton’s First Law, balanced forces could mean constant speed OR stationary, in this case the skydiver must be moving at constant velocity or there would be no air resistance).
Explain the motion of a spaceship floating through space, at steady speed, in terms of Newton’s Laws.
Newton’s 1st Law states that an object will stay at rest or move in a straight line at a steady speed if the forces acting on it are balanced.
