Forces and their interactions

Question 1

What is a scalar quantity?

Answer 1

• only have a magnitude

Question 2

What is a vector quantity?

Answer 2

• have a magnitude and and a direction

Question 3

What is magnitude?

Answer 3

• a value for size

Question 4

What does the arrow represent for vector quantities?

Answer 4

• size of arrow determines magnitude
• direction of arrow determines direction of the vector

Question 5

What are some examples of scalar quantities?

Answer 5

• mass
• speed
• distance
• energy
• temperature

Question 6

What are some examples of vector quantities?

Answer 6

• force
• velocity
• displacement
• acceleration
• momentum

Question 7

What is a contact force?

Answer 7

• when objects are touching

Question 8

What is a non-contact force?

Answer 8

• when objects are not touching or are separated

Question 9

What are some examples of non contact forces?

Answer 9

• gravitational force
• magnetic force
• electromagnetic force

Question 10

What are some examples of contact forces?

Answer 10

• air resistance
• normal contact force
• friction
• tension

Question 11

What is a normal contact force?

Answer 11

• force at right angles to the surface
• eg. weight of book balanced by reaction force from the table

“normal” = at 90 degrees

Question 12

How do you calculate weight?

Answer 12

w = m x g

weight = N
mass = kg
g = N/kg

Question 13

How do you measure forces?

Answer 13

• using a newtonmeter
• calibrated spring balance (spring stretches fixed distance for each newton)
• weight of object considered to act at a single point known as centre of mass

Question 14

What is the gravitational field strength on earth?

Answer 14

9.8 N/kg

Question 15

What is a resultant force?

Answer 15

• single force that has same effects as many different forces acting together

Question 16

What does a pair of different sized forces acting in opposite directions cause?

Answer 16

• a resultant force
• unbalanced forces causes resultant force

Question 17

How do you calculate resultant forces?

Answer 17

• larger force - smaller force in opposite direction
• adding forces that act on the same side

Question 18

What is weight?

Answer 18

a force acting on a mass due to gravity

Question 19

What is mass?

Answer 19

the amount of matter that an object contains