Forces - [Mechanics 2].

Question 1

What 2 things can forces do?

Answer 1

• Change the motion of a particle.
• Change the shape of a particle.

Question 2

Is Force a Vector or Scalar Quantity?

Answer 2

Vector - it has size and direction.

Question 3

What units do Forces have?

Answer 3

Newtons (N).

Question 4

What are the 6 types of Force?

Answer 4

1. Weight.
2. Tension.
3. Thrust.
4. Normal Reaction Force.
5. Friction.
6. Drag.

Question 5

What is Weight?

Answer 5

• The mass measured under the force of Gravity.
• Non-contact force.
• Acts vertically downwards.

Question 6

What is Tension?

Answer 6

• 2 forces acting away from each other (pulling).
• Tension is constant.
• Found in Strings.

Question 7

What is Thrust?

Answer 7

• A type of Driving force.
• Comes from an engine.

Question 8

What is the Normal Reaction Force?

Answer 8

• Link to Newton’s 3^rd Law - Opposite Equal Forces.
• Acts perpendicular to a surface.

Question 9

What is Friction?

Answer 9

• A contact force between 2 surfaces.
• Acts against the desired motion.

Question 10

What is Drag?

Answer 10

• The force from an object moving through a fluid.
• Type of Air Resistance.
• Acts against motion.
• Stationary = no drag.
• Increases with speed and surface area.

Question 11

When resolving into an angle, multiply the magnitude of the force by the _________ of the angle.

Answer 11

Cosine (Rcosθ).

Side of Triangle touching the angle.

Question 12

When resolving away from an angle, multiply the magnitude of the force by the _________ of the angle.

Answer 12

Sine (Rsinθ).

Side of Triangle not touching the angle.

Question 13

The angle of a resolved vector can be found by what equation?

Answer 13

θ = tan^-1 (Vertical Component) / (Horizontal Component).

Question 14

When is an object in equilibrium?

Answer 14

• There is no resultant force.
• There is no resultant torque.

Part of Newton’s 1^st Law.

Question 15

For an inclined plane, what do we have to consider?

Answer 15

• Parallel to the plane.
• Perpendicular to the plane.

Question 16

What is Newton’s 1^st Law?

Answer 16

“An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force.”

Equilibrium Link.

Question 17

What is Newton’s 2^nd Law?

Answer 17

“The acceleration of an object depends on the mass of the object and the amount of force applied.”

F_R = m x a.

Question 18

What is Newtons 3^rd Law?

Answer 18

“Whenever one object exerts a force on another object, the second object exerts an equal and opposite force on the first.”

Question 19

What equation can you use to work out the Maximum Frictional Force?

Answer 19

F_max = μR.

Question 20

What general equation can you use to work out the Frictional Force?

Answer 20

F ≤ μR.