Topic 2 - Mechanics

Question 1

What must be true when using SUVAT?

Answer 1

Constant acceleration

Question 2

What does the gradient of a distance-time graph represent?

Answer 2

Speed

Question 3

What does the gradient of a displacement-time graph represent?

Answer 3

Velocity

Question 4

What does the gradient of a velocity time graph represent?

Answer 4

Acceleration

Question 5

Describe the shape of a velocity-time graph when travelling with uniform acceleration

Answer 5

Straight line

Question 6

Describe the shape of a velocity-time graph with non-uniform acceleration

Answer 6

Curved line

Question 7

Compare velocity-time graphs for acceleration and deceleration

Answer 7

Acceleration: positive gradient
Deceleration: negative gradient

Question 8

Define scalar quantity

Answer 8

Has magnitude but no fixed direction

Question 9

Define vector quantity

Answer 9

Has magnitude and fixed direction

Question 10

How is a vector quantity represented on a diagram?

Answer 10

-Arrow
-Arrow head = direction of quantity
-Length = magnitude

Question 11

Describe the relationship between the perpendicular components of a vector

Answer 11

Independent of each other

Question 12

State Newton’s 1st Law

Answer 12

An object will remain at rest/ constant velocity unless acted on by an external resultant force

Question 13

State Newton’s 2nd Law

Answer 13

Acceleration of an object is directly proportional to the resultant force and inversely proportional to its mass

Question 14

State the defining equation of Newton’s 2nd Law

Answer 14

F=ma

Question 15

Describe forces on an object travelling at terminal velocity

Answer 15

-Forces are balanced in vertical and horizontal components
-No resultant force, therefore no acceleration

Question 16

Define terminal velocity

Answer 16

Maximum speed of an object

Question 17

What is the acceleration at terminal velocity?

Answer 17

0ms^-2

Question 18

Define Newton’s 3rd Law

Answer 18

Every action has an equal and opposite reaction. This means that there is always a pair of forces acting on interacting objects

Question 19

Define moment

Answer 19

Turning effect of a force

Question 20

What distance is used to calculate a moment?

Answer 20

Perpendicular distance between the line of action of the force and the axis of rotation

Question 21

Define the principle of moments

Answer 21

For an object to be in equilibrium, sum of clockwise moments = sum of anticlockwise moments

Question 22

What is an object’s centre of gravity?

Answer 22

The single point through which the object’s entire weight can be said to act

Question 23

What will occur if the line of action an object’s center of gravity lies outside its base?

Answer 23

The object’s weight will produce a resultant moment and so if it’s unsupported, the object may fall