Principles in Engineering

Question 1

Name the base quantities in mechanics and their units.

Answer 1

Distance (m)
Time (s)
Mass (kg)
Temperature (K)

Question 2

How do we convert mph to kph?

Answer 2

Multiply by 1.609

Question 3

How do we convert mph to ms^-1?

Answer 3

Multiply by 0.477

Question 4

How do we convert hours to seconds?

Answer 4

Multiply by 3600

Question 5

How do we convert miles to kilometres?

Answer 5

Multiply by 1.609

Question 6

What is the definition of a force?

Answer 6

A push or pull that acts on an object due to the interaction with another object

Question 7

What is an externally applied force?

Answer 7

A generic or unspecified source of generating a push or a pull force on an object

Question 8

What is gravity?

Answer 8

Mass (m): kg
Weight: w = mg

Question 9

What is the value of gravitational acceleration?

Answer 9

9.81m/s^2

Question 10

What is the formula for spring force?

Answer 10

Spring force (F) = Spring constant (-k) x change in length (Δx)

Question 11

What is surface reaction force denoted by?

Answer 11

N

Question 12

What is Newton’s third law?

Answer 12

If object 1 exerts a force on object 2, object 2 exerts a force of the same magnitude but opposite in direction to object 1.

Question 13

Describe the behaviour of surface reaction force

Answer 13

• It’s always perpendicular to the surface of contact.
• it’s magnitude is always equal to the magnitude of the force exerted perpendicular to the contact surface.

Question 14

Describe how friction forces act on an object

Answer 14

Friction force will act on the object, opposite to the direction of movement.

Question 15

How do we calculate the magnitude of friction?

Answer 15

Friction (f) = friction coefficient (μ) x surface reaction force (N)

Question 16

What is the rule for traction forces on a cable/rope?

Answer 16

The magnitude of the cable force at both ends is equal.

Question 17

What is the definition of a vector?

Answer 17

A quantity with both magnitude and direction.

Question 18

What is the definition of scalars?

Answer 18

A quantity with magnitude but no direction.

Question 19

How do we calculate the resultant force?

Answer 19

1: Identify the types of forces acting on an object
2: establish the coordinate system and the direction of the applied forces
3: formulate the resultant force by adding the sum of the horizontal and vertical components.

Question 20

What is Newton’s second law?

Answer 20

Acceleration of an object is proportional to the force applied to it and inversely proportional to its mass. F =ma