Mechanics - equations, graphs, f = ma, work, energy and linear momentum

 

1 Kinematics and Motion Graphs

1 What are the units of velocity, and of acceleration?

................................ and ..............................

2 In a single word, what does the slope of a position-time graph represent?

.......................................................

3 In a single word, what does the integral on a velocity-time graph represent?

......................................................

4 How may each of these equatons be derived? Only a simple statement is required - do not show any working.

v = u + at

...................................................................................................................................................

...................................................................................................................................................

...................................................................................................................................................

 

Acceleration due to gravity

1 What exactly is the shape of the position-time graph when acceleration is constant?

.................................................................................................................................................................

2 What is the slope of the velocity-time graph when a ball (etc.) is in free fall clear of the floor?

.................................................................................................................................................................

3 What is the acceleration when the ball (etc. ) is at the top of its flight, and momentarily stationary?

................................................................................................................................................................

4 Why is the measured acceleration of a large rubber ball (falling in the lab) a little less than 9.80 m/s/s?

................................................................................................................................................................

 

2 Vectors and Equilibrium

1 How are forces added when they are not in a straight line?

.......................................................................................................................................................................................................

2 How is the difference in two vectors (forces) found?

.......................................................................................................................................................................................................

3 What exactly do we mean when we say that three (or more) forces acting at a point are balanced?

.......................................................................................................................................................................................................

4 What two conditions are required for a rigid body to be in equilibrium?

.......................................................................................................................................................................................................

5 What is the moment of a force?

.......................................................................................................................................................................................................

6 Where is the weight of an extended body said to act?

.......................................................................................................................................................................................................

 

3 Newton's Rules

This is a large section ... you need three main points .......

1 What is Newton's first rule in modern form?

.......................................................................................................................................................................................................

a Explain why you know that a car traveling at constant speed on a level road has no unbalanced forces acting on it.

.......................................................................................................................................................................................................

2 What is Newton's second rule in modern form?

.......................................................................................................................................................................................................

a Give one example of f = ma in practice.

.......................................................................................................................................................................................................

.......................................................................................................................................................................................................

b How exactly did we verify the equation f = ma using a ball, a force probe, a motion detector, and a rubber band?

.......................................................................................................................................................................................................

.......................................................................................................................................................................................................

.......................................................................................................................................................................................................

c Define inertia.

.......................................................................................................................................................................................................

3 What is Newton's third rule?

.......................................................................................................................................................................................................

a How did we verify the rule with two force probes and a rubber band?

.......................................................................................................................................................................................................

 

4 Projectiles

1 What is the shape of the path of a projectile in the absence of air resistance?

.......................................................................................................................................................................................................

2 What particular type of force gives this motion?

.......................................................................................................................................................................................................

3 What can you say about the horizontal velocity for 'projectile' motion?

.......................................................................................................................................................................................................

4 What is the equation of the trajectory (path) in vector form, neglecting air resistance?

.......................................................................................................................................................................................................

5 How does the time of flight depend on the maximum height reached?

.......................................................................................................................................................................................................

 

5 Friction and Skid distance

1 What is the symbol for the coefficient of friction (k) in the equation F = k N ?

.................................

2 What is the definition of N and when is N equal to mg (in a simple situation)?

.......................................................................................................................................................................................................

.......................................................................................................................................................................................................

3 There are two coefficients of friction - what are they - and which one is larger?

...............................................................................................................

................................................................................................................

4 How would you measure friction force in a way which avoids acceleration?

.......................................................................................................................................................................................................

.......................................................................................................................................................................................................

5 Why is skid distance D proportional to velocity squared.

............................................................................................................

............................................................................................................

............................................................................................................

Sliding on an incline

1 Draw and name the three forces acting on a block which is stationary on an incline.

............................................................................................................

............................................................................................................

............................................................................................................

2 Write down equations for the size of the components of mg parallel and perpendicular to the plane.

............................................................................................................

............................................................................................................

3 What do the symbols mean the well known equation m = tanq

............................................................................................................

............................................................................................................

6 Work and Kinetic Energy

1 How is the simple definition of work as force x displacement modified when the force is not constant?

.......................................................................................................................................................................................................

2 What unit is common to work and energy?

..........................................

3* How is initial KE related to the incidental damage suffered by people in collisions?

.......................................................................................................................................................................................................

4 What happens to kinetic energy in a collision?

.......................................................................................................................................................................................................

5 Why is the total energy graph for a bouncing ball a series of steps?

.......................................................................................................................................................................................................

 

7 Impulse, momentum and Collisions

1 How is the definition of impulse modified if the force is not constant?

.......................................................................................................................................................................................................

2 How is the change in a quantity defined - for instance the change in your salary from this week to the next?

.......................................................................................................................................................................................................

3 What is meant exactly by "the conservation of momentum"?

...............................................................................................................................

...............................................................................................................................

4 Why is it important to get the signs of the velocities right in a momentum calculation before and after a collision?

.......................................................................................................................................................................................................

5 Define the coefficient of restitution?

...............................................................................................................................

...............................................................................................................................

8 Power

1 Who first defined the quantity we now call power, and why?

.......................................................................................................................................................................................................

.......................................................................................................................................................................................................

2 How is power related to 'work'?

.......................................................................................................................................................................................................

3 What are the units of power?

............................................................................................................

4 How is the power available in a fluid flow related to the mass per second and the velocity of the flow?

...................................................................................................

....................................................................................................