Mechanics 2 - Linear and Projectile Motion Flashcards by Daniel Mawson

Q

What is displacement and how is it different to distance?

A

Displacement is a measure of the line connecting the starting point to the finishing point.

Distance is a measure of the total length of the path travelled.

Also distance is a scalar and displacement is a vector.

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What does a straight line on a distance-time graph represent?

A

A constant speed.

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

How is acceleration defined?

A

Acceleration is the rate of change of velocity.

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

How is speed different to velocity?

A

Speed is the rate of change of distance.

Velocity is the rate of change of displacement.

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Describe the motion of this ball

A

Ball is moving to the right and speeding up.

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Decribe the motion of this ball.

A

Ball is moving to the left and speeding up.

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Describe the motion of this ball.

A

Ball is moving to the right and slowing down.

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Describe the motion of this ball.

A

Ball is moving to the left but slowing down.

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Is the ball moving to the right?

A

Only if the velocity vector is also acting to the right.

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What does a straight line on a displacement-time graph represent?

A

A constant velocity.

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What does a curve with an increasing gradient represent on a displacement-time graph?

A

An increasing velocity (acceleration)

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What does a curve with a decreasing gradient represent on a displacement-time graph?

A

A decreasing velocity (decceleration)

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What does a negative gradient on a displacement-time graph represent?

A

A negative velocity (travelling back to where it started)

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What does a straight line on a velocity-time graph represent?

A

A constant acceleration.

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What does a curve with an increasing gradient represent on a velocity-time graph?

A

An increasing acceleration.

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What does a curve with a decreasing gradient represent on a velocity-time graph?

A

A decreasing acceleration.

Q

What does a negative gradient on a velocity-time graph represent?

A

A negative acceleration.

Q

What does this graph show?

A

A ball bouncing off a surface

(Dotted lines represent the bounce)

(Red lines represent the ball accelerating towards the ground)

Q

What does the acceleration time graph of a ball in freefall look like?

A

Constant acceleration of 9.81ms-2

Q

What does the area of a speed-time graph represent?

How about a velocity-time graph?

A

Q

What’s wrong with this?

A

Displacement takes direction into account.

It should be…

Q

When can you use this equation?

A

When the acceleration = 0 (constant velocity)

Or to work out an average speed

Q

When can you use SUVATs?

A

When acceleration is constant

Or if object has stages of constant acceleration

Q

Why can’t you use SUVAT’s when working with this graph?

A

Because the acceleration (gradient) is changing

What does it mean if an object is in freefall?

Only **weight is acting on the object** It has a constant **acceleration of 9.81ms-2** acting downawards (on Earth)

If one ball is dropped as another is projected horizontally which hits the ground first?

They both hit the ground at the same time... Both in freefall so accelerate at 9.81ms-2 **Vertical motion independent of horizontal motion**

What's wrong with this labelling?

Initial velocity and final velocity are not 0

In projectile motion when is the vertical component of the velocity 0?

At the peak of a parabola ## Footnote **Not at the start or end**

How do you start a question involving **angled projectile motion?**

Resolve the velocity into vertical and horizontal components and fill out the corresponding SUVATs

What is wrong here?

The acceleration is only 9.81ms^-2 if the object is in freefall