PHYSICS TEST CHAPTER 3.1 Flashcards
Define force
A force is that which changes or tends to change and object’s state of rest or uniform motion in a straight line.
Where would someone experience the effects of weightlessness
A person may experience the effects of weightlessness in outer space (where there is no gravity).
In physics what do you understand by the word “weightlessness”
Weightlessness means there is no pull of gravity.
A robot weighs 2000 N on Earth. Using formula, calculate mass of robot on Earth
Given Wanted
Weight = 2000 N Mass, M = ?
Solution
Mass = weight divided by gravity
Mass = 2000 N divided by 10 N/kg
= 200 kg
Calculate its mass on Mars without workout
His mass is 200 kg because mass never changes
Find weight on Mars where g = 3.5 N/kg
Given Wanted
Gravity, G = 3.5 N/kg Weight, W = ?
Mass, M = 200 kg
Solution
Weight = mass x gravity
Weight = 200 kg x 3.5 N/kg
= 700 N
List 2 positive and 2 negative effects of friction
POSITIVE EFFECTS
a) When we want things to stop, friction is helpful.
b) The friction on our shoes and the ground prevent us from slipping.
NEGATIVE EFFECTS:
a) When we want things to move, friction is a nuisance
b) Friction causes wear and tear in moving parts in machinery and motors.
State Hooke’s Law for springs
When an elastic object (spring) is stretched to the stretching force is proportional to the extension of the object, provided the force is not so not so great that it deforms the object permanently.
TYPES OF FORCES THAT MATCH WITH EACH DESCRIPTION
A person uses a rope to pull a friend on a sled - tension
A magnet holds a picture on a fridge - magnetic force
When a person stops pedalling, the bicycle slows down - friction
A meteor travelling through space moves faster and faster as it
approaches Earth - gravity
Your hands become warmer as you vigorously rub them together - friction
lift/normal force?
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drag < - - - - AIRPLANE - - - - - -> thrust
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gravity
The forces acting upwards and downwards are equal which is why the plane is steady.
