AQA AS PHYSICS QUESTIONS WITH CERTIFIED REVISED
ANSWERS FOR BETTER GRADES GARANTEED 100% PASS
REVIEWED BY ACEMARKET
Forces, Vectors, and Work – Question & Answer Summary
What are non-contact forces?
Non-contact forces act without physical contact, such as gravity and magnetic force.
What is mass?
Mass is the amount of matter in an object. It is a scalar quantity.
What is weight?
Weight is the force caused by gravity acting on an object. Since gravity has direction,
weight is a vector.
What is the value of gravity on Earth?
Gravity on Earth is approximately 9.81 m/s².
What is the equation for weight?
Weight = Mass × Gravity
(This formula can be rearranged.)
How does gravity on the Moon compare to Earth?
The Moon has less gravity, so objects weigh less, but their mass stays the same.
There is no air resistance on the Moon, so all objects fall at the same rate.
, What is a resultant force?
A resultant force is the single force that replaces two or more forces acting on an object.
How do you find a resultant force?
If forces act in the same or opposite direction, add or subtract them.
If forces act at an angle:
• Draw a scale diagram
• Measure tip-to-tip distance
• Use a protractor to find the direction
What does it mean to resolve a force?
Resolving a force means splitting it into horizontal and vertical components using
trigonometry.
What is work done?
Work done is the transfer of energy when a force moves an object. It is a scalar.
What is the equation for work done?
Work = Force × Displacement
What units are used for work?
Work is measured in joules (J) or newton metres (Nm).
1 Nm = 1 J
F∝e → F=ke
the extension of the spring is directly proportional to the force exerted on it
, extension (e)
the difference between the original length and the extended length
spring constant (k)
how much the spring stretches with a given force
Hooke's law
states that the strain in a solid (e.g. a spring) is proportional to the applied stress (within the
elastic limit of that solid)
Ee (elastic energy)
= 0.5ke²
(the energy topic is covered in more detail in paper 1)
moment
the moment of a force is the turning effect it has on an object connected to a pivot - for an
object with a pivot to be in equilibrium the moments must be equal
M (Nm)
= F (N) X d (m) (the unit for moments is Nm and not J as a moment is a turning effect, not an
energy)
gears
use the principle of moments to transmit a turning effect - different sized gears can be used to
change a moment - a gear turns in the opposite direction to the gear it is attached to - gear =
cog
centre of mass
the point in an object at which its mass can be thought of as being concentrated
pressure
the amount of force exerted per unit squared of the area of the object
fluids
substances that flow because their particles are able to move around - fluids include liquids and
gases
ANSWERS FOR BETTER GRADES GARANTEED 100% PASS
REVIEWED BY ACEMARKET
Forces, Vectors, and Work – Question & Answer Summary
What are non-contact forces?
Non-contact forces act without physical contact, such as gravity and magnetic force.
What is mass?
Mass is the amount of matter in an object. It is a scalar quantity.
What is weight?
Weight is the force caused by gravity acting on an object. Since gravity has direction,
weight is a vector.
What is the value of gravity on Earth?
Gravity on Earth is approximately 9.81 m/s².
What is the equation for weight?
Weight = Mass × Gravity
(This formula can be rearranged.)
How does gravity on the Moon compare to Earth?
The Moon has less gravity, so objects weigh less, but their mass stays the same.
There is no air resistance on the Moon, so all objects fall at the same rate.
, What is a resultant force?
A resultant force is the single force that replaces two or more forces acting on an object.
How do you find a resultant force?
If forces act in the same or opposite direction, add or subtract them.
If forces act at an angle:
• Draw a scale diagram
• Measure tip-to-tip distance
• Use a protractor to find the direction
What does it mean to resolve a force?
Resolving a force means splitting it into horizontal and vertical components using
trigonometry.
What is work done?
Work done is the transfer of energy when a force moves an object. It is a scalar.
What is the equation for work done?
Work = Force × Displacement
What units are used for work?
Work is measured in joules (J) or newton metres (Nm).
1 Nm = 1 J
F∝e → F=ke
the extension of the spring is directly proportional to the force exerted on it
, extension (e)
the difference between the original length and the extended length
spring constant (k)
how much the spring stretches with a given force
Hooke's law
states that the strain in a solid (e.g. a spring) is proportional to the applied stress (within the
elastic limit of that solid)
Ee (elastic energy)
= 0.5ke²
(the energy topic is covered in more detail in paper 1)
moment
the moment of a force is the turning effect it has on an object connected to a pivot - for an
object with a pivot to be in equilibrium the moments must be equal
M (Nm)
= F (N) X d (m) (the unit for moments is Nm and not J as a moment is a turning effect, not an
energy)
gears
use the principle of moments to transmit a turning effect - different sized gears can be used to
change a moment - a gear turns in the opposite direction to the gear it is attached to - gear =
cog
centre of mass
the point in an object at which its mass can be thought of as being concentrated
pressure
the amount of force exerted per unit squared of the area of the object
fluids
substances that flow because their particles are able to move around - fluids include liquids and
gases
