forces movement shape and momentum

Question 1

What can forces do to a body

Answer 1

• can act on a body to change shape:
  → stretch, squish, twist
• Change velocity
  → change direction, speed, or both

Question 2

Remember these forces

Answer 2

• air resistance
• tension
• up thrust
• lift
• thrust
• electrostatic

Question 3

Example of scalar and vector

Answer 3

Vector: displacement, acceleration, Force
Scalar: distance, time

Question 4

What is friction!

Answer 4

• goes against motion

Question 5

Thinking distance affected by:

Answer 5

• tiredness
• alcohol
• speed of the car
• drugs

Question 6

Braking distance affected by:

Answer 6

• Road conditions
• Tyre conditions
• Brake conditions
• Speed and mass of the car

Question 7

Terminal velocity journey

Answer 7

1. Only force is weight
2. Object then accelerates downward
3. Then velocity increases so therefore drag also increases
4. There is a smaller resultant force downward so therefore acceleration decreases
5. The object reaches a speed where the drag is equal to weight

Question 8

Extension varying with applied force

Answer 8

• Hang spring on a clamp stand, put a mass hanger on spring, put half metre ruler on the side.
• repeat with different mass increasing by grams of 100
• put results on a table
  → should have a limit of proportionality.

Question 9

Hooke’s law and elastic behaviour

Answer 9

• Extension directly proportional to force applied
• the ability of a material to recover original shape after the force is removed. In a spring this occurs when the force is lower than elastic limit.

Question 10

How to explain my terminal velocity misconception

Answer 10

• weight is a force, mass times 10n/kg on earth
• (heavier objects need more drag to make resultant force equal zero)
• the weight accelerates, increases velocity of the object at a pace as it goes down.
• increase in velocity increases air resistance
• air resistance increases at the rate of velocity increases until it reaches the same as weight

Question 11

Car safety

Answer 11

• front and rear crumple zones
• seat belts
• air bags

Question 12

Conservation of momentum

Answer 12

• momentum of 2 things separately before = momentum after (combined mass * combined velocity)

Question 13

Principle of moments

Answer 13

Anticlockwise moment = clockwise moment