Topic 9 Forces Around You

Question 1

What is Newton’s first law of motion?

Answer 1

An object remains at rest or moves in a straight line at constant speed unless it is acted on by an unbalanced force

Question 2

How do you calculate speed?

Answer 2

Distance / time

Question 3

What is the abbreviated for speed?

Answer 3

v

Question 4

What is the abbreviated for distance?

Answer 4

d

Question 5

What is the abbreviated for time?

Answer 5

t

Question 6

What is an unbalanced force?

Answer 6

It is a single force that is applied to an object to change its direction

Question 7

If two forces are applied to opposite direction of an object what is this called?

Answer 7

Balanced force - this is usually of equal strength

Question 8

Define equilibrium

Answer 8

Any object that is subject to balanced forces is said to be in equilibrium

Question 9

In terms of equilibrium if an object stays at rest what is this called?

Answer 9

Static equilibrium

Any object that is subjected to balanced forces

Question 10

In terms of equilibrium if an object is moving at constant speed, what is this called?

Answer 10

Dynamic equilibrium

Any object that is subjected to balanced forces

Question 11

How do you calculate weight?

Answer 11

weight = mass × acceleration due to gravity

Question 12

How can this be written using symbols?

Answer 12

W = m × g or W = mg

Question 13

What is the abbreviated for weight?

Answer 13

W

Question 14

What is the abbreviated for mass?

Answer 14

m

Question 15

What is the abbreviated for gravity

Answer 15

g

Question 16

When symbols are written next to each other what does this imply?

Answer 16

They should be multiplied
e.g.
W = mg

Question 17

Close to the earths surface what is the value of gravity?

Answer 17

9.81 m s−2

for less precise calculations you can use 10 m s−2.

Question 18

What is mass?

Answer 18

Mass is a measure of how much matter an object is made of

Question 19

What is weight?

Answer 19

weight is the force that our planet exerts on that matter.

weight is a force, it also has a direction, so we have to say that the weight of an object is W = mg downwards

Question 20

Is it correct to say ‘My weight is 90 kg’?

Answer 20

we say ‘My weight is 90 kg’, but the correct statement is ‘My mass is 90 kg’. Since weight is a force, it also has a direction, so we have to say that the weight of an object is W = mg downwards

Question 21

What is the value of a newton?

Answer 21

1 kg m s−2

Question 22

What is the abbreviation of a newton?

Answer 22

N