P8- Forces in balance 🚂🏎️

Question 1

What are examples of scalar quantities ?

Hint: mass, temperature

Answer 1

• mass
• temperature
• speed
• energy
• distance
• time

Question 2

What are scalar ?

Hint: magnitude/direction

Answer 2

• a scalar, is a physical quantity [e.g- mass or energy], that has magnitude [size] only [unlike a vector]

Question 3

What are examples of vector quantities ?

Hint: velocity, moment

Answer 3

• displacement
• weight
• force
• velocity
• acceleration
• momentum

Question 4

What is a vector ?

Answer 4

• a vector, is a physical quantity [e.g- displacement or velocity], that has a magnitude [size], and a direction, unlike a scalar.

Question 5

What does quantity mean ?

Answer 5

• quantity means, the total amount or number of something.

Question 6

What is the difference between a scalar 🆚 a vector ?

Answer 6

• a scalar, is a physical quantity [e.g- mass or energy], that has magnitude [size] only [unlike a vector]
• ; a vector, is a physical quantity [e.g- displacement or velocity], that has a magnitude [size], and a direction, unlike a scalar.

Question 7

What quantity is distance 🆚️ displacement ? Explain your answer.

Answer 7

• distance, is a scalar quantity because it gives us no idea about direction.
• ; displacement is a vector quality, since displacement is distance in a specific direction. [the magnitude has to be stated, aswell as the direction]

Question 8

Explain how can vectors be represented

Answer 8

• vectors can be represented with an arrow because, the length of the arrow represents the magnitude of the vector
• and the direction of the arrow represents the direction of the vector.

Question 9

What is a force

Hint: push or pull- why?

Answer 9

• a force, is a push or a pull that acts on an object, due to the interaction with another object.
• all forces have both magnitude [size] and a direction, therefore forces are a vector quantity.

Question 10

What is the unit of force ?

Answer 10

• the unit of force, is the newton (N)

Question 11

What are contact and non-contact forces?

Answer 11

• contact forces, is when two objects are physically touching.
• An example of this, is tension in a rope. In the case of tug of war, this force of tension is pulling on a person

Question 12

Name all the contact forces

Answer 12

• tension in a rope
• friction
• air resistance [drag]
• normal contact force [reaction force]

Question 13

What are some examples of contact forces ? 🪢

Answer 13

• tension in a rope. In the case of tug of war, this force of tension is pulling on a person

Question 14

What are some examples of contact forces ? 🛩️

Answer 14

• friction- if an aeroplane was landing on the sea, the force of friction is what is acting bewteen the water and the aeroplane.
• and therefore causing the aeroplane to slow down, and come to a stop.

Question 15

What are some examples of contact forces ? 🪂

Answer 15

• air resistance or drag- in skydiving, as the skydiver falls through the air, air particles collide with the parachute and causes the force of air resistance, to act upwards.

Question 16

What are some examples of contact forces ? 💡🏮

Answer 16

• normal contact force [reaction force]- if a lamp is on a table, it exerts a downwards force on the table- the weight of the lamp.
• ; at the same time, the table is exerting an upwards force on the lamp. This is called the normal contact force, which can only happen if the two objects are in direct contact.

Question 17

What is another example of a normal contact force ? 🪑

Answer 17

• a chair- a chair exerts a force on the ground; the ground pushes back at the chair with the same force.
• This is another example of normal contact force because, equal but opposite forces are felt by both the chair and the ground.

Question 18

What is a non-contact force ?

Answer 18

• a non-contact force, is where two objects are physically separated.

Question 19

List some non-contact forces

Answer 19

• gravitational force
• electrostatic force
• magnetic force

Question 21

What are some examples of non-contact forces ? 🛰️

Hint: attracts

Answer 21

• gravitational force- this attracts all objects to other objects.
• For example, the gravitational force attracts the international space station, to the Earth. and the Earth to the international space station. [vice versa]

Question 21

What are some examples of non-contact forces ? ⚡️

Hint: charged

Answer 21

• electrostatic force- this is the force between two charged objects. This is because, objects with opposite charges experience an electrostatic force of attraction.
• ; objects with the same type of charge, will experience an electrostatic force of repulsion.
• Moreover, in both cases, the two objects are physically separated from each other as, the electrostatic force is a non-contact force. [e.g- lightning striking Earth]

Question 22

What are some examples of non-contact forces ? 🧲

Hint: field

Answer 22

• magnetic force- this is the force experienced by certain objects, in a magnetic field.